diff --git a/modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml b/modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
index 8a003841821..2e6be05a4b0 100644
--- a/modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/csharp/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
@@ -848,6 +848,14 @@ paths:
         - fake
       description: Test serialization of outer string types
       operationId: fakeOuterStringSerialize
+      parameters:
+        - name: required_string_uuid
+          in: query
+          description: Required UUID String
+          required: true
+          schema:
+            type: string
+            format: uuid
       responses:
         '200':
           description: Output string
@@ -1621,6 +1629,10 @@ components:
     MixedPropertiesAndAdditionalPropertiesClass:
       type: object
       properties:
+        uuid_with_pattern:
+          type: string
+          format: uuid
+          pattern: "[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}"
         uuid:
           type: string
           format: uuid
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/FakeApi.md
index 212d1d35c49..4b5bf803c4e 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/MixedPropertiesAndAdditionalPropertiesClass.md
index 5f57db957d7..050210a3e37 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -4,6 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
+**UuidWithPattern** | **Guid** |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs
index 5991b7f0b78..ca68e330338 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -121,10 +121,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0);
+        string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
 
         /// <summary>
         /// 
@@ -133,10 +134,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0);
+        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -529,11 +531,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
 
         /// <summary>
         /// 
@@ -542,11 +545,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -1509,12 +1513,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        public string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0)
+        public string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(body);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
             return localVarResponse.Data;
         }
 
@@ -1522,10 +1527,11 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0)
+        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
@@ -1550,6 +1556,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
@@ -1574,13 +1581,14 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(body, operationIndex, cancellationToken).ConfigureAwait(false);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, operationIndex, cancellationToken).ConfigureAwait(false);
             return localVarResponse.Data;
         }
 
@@ -1588,11 +1596,12 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
 
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
@@ -1618,6 +1627,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index f4c0f85ea8d..de88a24f150 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -35,11 +35,17 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Initializes a new instance of the <see cref="MixedPropertiesAndAdditionalPropertiesClass" /> class.
         /// </summary>
+        /// <param name="uuidWithPattern">uuidWithPattern.</param>
         /// <param name="uuid">uuid.</param>
         /// <param name="dateTime">dateTime.</param>
         /// <param name="map">map.</param>
-        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
+        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuidWithPattern = default(Guid), Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
         {
+            this._UuidWithPattern = uuidWithPattern;
+            if (this.UuidWithPattern != null)
+            {
+                this._flagUuidWithPattern = true;
+            }
             this._Uuid = uuid;
             if (this.Uuid != null)
             {
@@ -58,6 +64,30 @@ namespace Org.OpenAPITools.Model
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [DataMember(Name = "uuid_with_pattern", EmitDefaultValue = false)]
+        public Guid UuidWithPattern
+        {
+            get{ return _UuidWithPattern;}
+            set
+            {
+                _UuidWithPattern = value;
+                _flagUuidWithPattern = true;
+            }
+        }
+        private Guid _UuidWithPattern;
+        private bool _flagUuidWithPattern;
+
+        /// <summary>
+        /// Returns false as UuidWithPattern should not be serialized given that it's read-only.
+        /// </summary>
+        /// <returns>false (boolean)</returns>
+        public bool ShouldSerializeUuidWithPattern()
+        {
+            return _flagUuidWithPattern;
+        }
         /// <summary>
         /// Gets or Sets Uuid
         /// </summary>
@@ -144,6 +174,7 @@ namespace Org.OpenAPITools.Model
         {
             StringBuilder sb = new StringBuilder();
             sb.Append("class MixedPropertiesAndAdditionalPropertiesClass {\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
@@ -190,6 +221,10 @@ namespace Org.OpenAPITools.Model
             unchecked // Overflow is fine, just wrap
             {
                 int hashCode = 41;
+                if (this.UuidWithPattern != null)
+                {
+                    hashCode = (hashCode * 59) + this.UuidWithPattern.GetHashCode();
+                }
                 if (this.Uuid != null)
                 {
                     hashCode = (hashCode * 59) + this.Uuid.GetHashCode();
@@ -217,6 +252,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/docs/apis/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/docs/apis/FakeApi.md
index 77826f0673b..acdcf538944 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/docs/apis/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/docs/apis/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string? body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string? body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string? | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string?** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
index 0bac85a8e83..1bc0740add9 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -7,6 +7,7 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
+**UuidWithPattern** | **Guid** |  | [optional] 
 
 [[Back to Model list]](../../README.md#documentation-for-models) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to README]](../../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
index 84ff71fb14d..f3827621211 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
@@ -100,8 +100,9 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterStringSerializeAsyncTest()
         {
+            Guid requiredStringUuid = default;
             string? body = default;
-            var response = await _instance.FakeOuterStringSerializeAsync(body);
+            var response = await _instance.FakeOuterStringSerializeAsync(requiredStringUuid, body);
             Assert.IsType<string>(response);
         }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/FakeApi.cs
index 8732ee2357c..e9cca0ad46c 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -173,10 +173,11 @@ namespace Org.OpenAPITools.IApi
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;string?&gt;&gt;</returns>
-        Task<ApiResponse<string?>> FakeOuterStringSerializeWithHttpInfoAsync(string? body = null, System.Threading.CancellationToken? cancellationToken = null);
+        Task<ApiResponse<string?>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string? body = null, System.Threading.CancellationToken? cancellationToken = null);
 
         /// <summary>
         /// 
@@ -185,10 +186,11 @@ namespace Org.OpenAPITools.IApi
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse&lt;string&gt;</returns>
-        Task<string> FakeOuterStringSerializeAsync(string? body = null, System.Threading.CancellationToken? cancellationToken = null);
+        Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string? body = null, System.Threading.CancellationToken? cancellationToken = null);
 
         /// <summary>
         /// 
@@ -196,10 +198,11 @@ namespace Org.OpenAPITools.IApi
         /// <remarks>
         /// Test serialization of outer string types
         /// </remarks>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse&lt;string?&gt;</returns>
-        Task<string?> FakeOuterStringSerializeOrDefaultAsync(string? body = null, System.Threading.CancellationToken? cancellationToken = null);
+        Task<string?> FakeOuterStringSerializeOrDefaultAsync(Guid requiredStringUuid, string? body = null, System.Threading.CancellationToken? cancellationToken = null);
 
         /// <summary>
         /// Array of Enums
@@ -1294,12 +1297,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="string"/>&gt;</returns>
-        public async Task<string> FakeOuterStringSerializeAsync(string? body = null, System.Threading.CancellationToken? cancellationToken = null)
+        public async Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string? body = null, System.Threading.CancellationToken? cancellationToken = null)
         {
-            ApiResponse<string?> result = await FakeOuterStringSerializeWithHttpInfoAsync(body, cancellationToken).ConfigureAwait(false);
+            ApiResponse<string?> result = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, cancellationToken).ConfigureAwait(false);
 
             if (result.Content == null)
                 throw new ApiException(result.ReasonPhrase, result.StatusCode, result.RawContent);
@@ -1311,15 +1315,16 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="string"/>&gt;</returns>
-        public async Task<string?> FakeOuterStringSerializeOrDefaultAsync(string? body = null, System.Threading.CancellationToken? cancellationToken = null)
+        public async Task<string?> FakeOuterStringSerializeOrDefaultAsync(Guid requiredStringUuid, string? body = null, System.Threading.CancellationToken? cancellationToken = null)
         {
             ApiResponse<string?>? result = null;
             try 
             {
-                result = await FakeOuterStringSerializeWithHttpInfoAsync(body, cancellationToken).ConfigureAwait(false);
+                result = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, cancellationToken).ConfigureAwait(false);
             }
             catch (Exception)
             {
@@ -1333,19 +1338,30 @@ namespace Org.OpenAPITools.Api
         /// <summary>
         /// Validates the request parameters
         /// </summary>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
         /// <returns></returns>
-        protected virtual string? OnFakeOuterStringSerialize(string? body)
+        protected virtual (Guid, string?) OnFakeOuterStringSerialize(Guid requiredStringUuid, string? body)
         {
-            return body;
+            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+
+            if (requiredStringUuid == null)
+                throw new ArgumentNullException(nameof(requiredStringUuid));
+
+            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+
+            return (requiredStringUuid, body);
         }
 
         /// <summary>
         /// Processes the server response
         /// </summary>
         /// <param name="apiResponse"></param>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
-        protected virtual void AfterFakeOuterStringSerialize(ApiResponse<string?> apiResponse, string? body)
+        protected virtual void AfterFakeOuterStringSerialize(ApiResponse<string?> apiResponse, Guid requiredStringUuid, string? body)
         {
         }
 
@@ -1355,8 +1371,9 @@ namespace Org.OpenAPITools.Api
         /// <param name="exception"></param>
         /// <param name="pathFormat"></param>
         /// <param name="path"></param>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
-        protected virtual void OnErrorFakeOuterStringSerialize(Exception exception, string pathFormat, string path, string? body)
+        protected virtual void OnErrorFakeOuterStringSerialize(Exception exception, string pathFormat, string path, Guid requiredStringUuid, string? body)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
         }
@@ -1365,16 +1382,19 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="string"/></returns>
-        public async Task<ApiResponse<string?>> FakeOuterStringSerializeWithHttpInfoAsync(string? body = null, System.Threading.CancellationToken? cancellationToken = null)
+        public async Task<ApiResponse<string?>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string? body = null, System.Threading.CancellationToken? cancellationToken = null)
         {
             UriBuilder uriBuilder = new UriBuilder();
 
             try
             {
-                body = OnFakeOuterStringSerialize(body);
+                var validatedParameters = OnFakeOuterStringSerialize(requiredStringUuid, body);
+                requiredStringUuid = validatedParameters.Item1;
+                body = validatedParameters.Item2;
 
                 using (HttpRequestMessage request = new HttpRequestMessage())
                 {
@@ -1383,6 +1403,12 @@ namespace Org.OpenAPITools.Api
                     uriBuilder.Scheme = ClientUtils.SCHEME;
                     uriBuilder.Path = ClientUtils.CONTEXT_PATH + "/fake/outer/string";
 
+                    System.Collections.Specialized.NameValueCollection parseQueryString = System.Web.HttpUtility.ParseQueryString(string.Empty);
+
+                    parseQueryString["required_string_uuid"] = Uri.EscapeDataString(requiredStringUuid.ToString()!);
+                    
+                    uriBuilder.Query = parseQueryString.ToString();
+
                     request.Content = (body as object) is System.IO.Stream stream
                         ? request.Content = new StreamContent(stream)
                         : request.Content = new StringContent(JsonSerializer.Serialize(body, _jsonSerializerOptions));
@@ -1424,7 +1450,7 @@ namespace Org.OpenAPITools.Api
                         if (apiResponse.IsSuccessStatusCode)
                         {
                             apiResponse.Content = JsonSerializer.Deserialize<string>(apiResponse.RawContent, _jsonSerializerOptions);
-                            AfterFakeOuterStringSerialize(apiResponse, body);
+                            AfterFakeOuterStringSerialize(apiResponse, requiredStringUuid, body);
                         }
 
                         return apiResponse;
@@ -1433,7 +1459,7 @@ namespace Org.OpenAPITools.Api
             }
             catch(Exception e)
             {
-                OnErrorFakeOuterStringSerialize(e, "/fake/outer/string", uriBuilder.Path, body);
+                OnErrorFakeOuterStringSerialize(e, "/fake/outer/string", uriBuilder.Path, requiredStringUuid, body);
                 throw;
             }
         }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 5283098e113..1e9d78c798c 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0-nrt/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -36,12 +36,16 @@ namespace Org.OpenAPITools.Model
         /// <param name="dateTime">dateTime</param>
         /// <param name="map">map</param>
         /// <param name="uuid">uuid</param>
+        /// <param name="uuidWithPattern">uuidWithPattern</param>
         [JsonConstructor]
-        public MixedPropertiesAndAdditionalPropertiesClass(DateTime dateTime, Dictionary<string, Animal> map, Guid uuid)
+        public MixedPropertiesAndAdditionalPropertiesClass(DateTime dateTime, Dictionary<string, Animal> map, Guid uuid, Guid uuidWithPattern)
         {
 #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
 #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
 
+            if (uuidWithPattern == null)
+                throw new ArgumentNullException("uuidWithPattern is a required property for MixedPropertiesAndAdditionalPropertiesClass and cannot be null.");
+
             if (uuid == null)
                 throw new ArgumentNullException("uuid is a required property for MixedPropertiesAndAdditionalPropertiesClass and cannot be null.");
 
@@ -57,6 +61,7 @@ namespace Org.OpenAPITools.Model
             DateTime = dateTime;
             Map = map;
             Uuid = uuid;
+            UuidWithPattern = uuidWithPattern;
         }
 
         /// <summary>
@@ -77,6 +82,12 @@ namespace Org.OpenAPITools.Model
         [JsonPropertyName("uuid")]
         public Guid Uuid { get; set; }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [JsonPropertyName("uuid_with_pattern")]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets additional properties
         /// </summary>
@@ -94,6 +105,7 @@ namespace Org.OpenAPITools.Model
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  AdditionalProperties: ").Append(AdditionalProperties).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
@@ -105,6 +117,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
@@ -134,6 +153,7 @@ namespace Org.OpenAPITools.Model
             DateTime dateTime = default;
             Dictionary<string, Animal> map = default;
             Guid uuid = default;
+            Guid uuidWithPattern = default;
 
             while (utf8JsonReader.Read())
             {
@@ -159,13 +179,16 @@ namespace Org.OpenAPITools.Model
                         case "uuid":
                             uuid = utf8JsonReader.GetGuid();
                             break;
+                        case "uuid_with_pattern":
+                            uuidWithPattern = utf8JsonReader.GetGuid();
+                            break;
                         default:
                             break;
                     }
                 }
             }
 
-            return new MixedPropertiesAndAdditionalPropertiesClass(dateTime, map, uuid);
+            return new MixedPropertiesAndAdditionalPropertiesClass(dateTime, map, uuid, uuidWithPattern);
         }
 
         /// <summary>
@@ -184,6 +207,7 @@ namespace Org.OpenAPITools.Model
             writer.WritePropertyName("map");
             JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);
             writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
+            writer.WriteString("uuid_with_pattern", mixedPropertiesAndAdditionalPropertiesClass.UuidWithPattern);
 
             writer.WriteEndObject();
         }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/docs/apis/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/docs/apis/FakeApi.md
index b815f20b5a0..1b47e75a7dd 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/docs/apis/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/docs/apis/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
index 0bac85a8e83..1bc0740add9 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -7,6 +7,7 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
+**UuidWithPattern** | **Guid** |  | [optional] 
 
 [[Back to Model list]](../../README.md#documentation-for-models) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to README]](../../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
index 4c965120e69..0ba3c2103cf 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
@@ -100,8 +100,9 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterStringSerializeAsyncTest()
         {
+            Guid requiredStringUuid = default;
             string body = default;
-            var response = await _instance.FakeOuterStringSerializeAsync(body);
+            var response = await _instance.FakeOuterStringSerializeAsync(requiredStringUuid, body);
             Assert.IsType<string>(response);
         }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/FakeApi.cs
index 0c0b289c532..cb0bb021040 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -128,10 +128,11 @@ namespace Org.OpenAPITools.IApi
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;string&gt;&gt;</returns>
-        Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = null, System.Threading.CancellationToken? cancellationToken = null);
+        Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = null, System.Threading.CancellationToken? cancellationToken = null);
 
         /// <summary>
         /// 
@@ -140,10 +141,11 @@ namespace Org.OpenAPITools.IApi
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse&lt;string&gt;</returns>
-        Task<string> FakeOuterStringSerializeAsync(string body = null, System.Threading.CancellationToken? cancellationToken = null);
+        Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = null, System.Threading.CancellationToken? cancellationToken = null);
 
         /// <summary>
         /// Array of Enums
@@ -1056,12 +1058,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="string"/>&gt;</returns>
-        public async Task<string> FakeOuterStringSerializeAsync(string body = null, System.Threading.CancellationToken? cancellationToken = null)
+        public async Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = null, System.Threading.CancellationToken? cancellationToken = null)
         {
-            ApiResponse<string> result = await FakeOuterStringSerializeWithHttpInfoAsync(body, cancellationToken).ConfigureAwait(false);
+            ApiResponse<string> result = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, cancellationToken).ConfigureAwait(false);
 
             #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
             if (result.Content == null)
@@ -1074,19 +1077,30 @@ namespace Org.OpenAPITools.Api
         /// <summary>
         /// Validates the request parameters
         /// </summary>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
         /// <returns></returns>
-        protected virtual string OnFakeOuterStringSerialize(string body)
+        protected virtual (Guid, string) OnFakeOuterStringSerialize(Guid requiredStringUuid, string body)
         {
-            return body;
+            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+
+            if (requiredStringUuid == null)
+                throw new ArgumentNullException(nameof(requiredStringUuid));
+
+            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+
+            return (requiredStringUuid, body);
         }
 
         /// <summary>
         /// Processes the server response
         /// </summary>
         /// <param name="apiResponse"></param>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
-        protected virtual void AfterFakeOuterStringSerialize(ApiResponse<string> apiResponse, string body)
+        protected virtual void AfterFakeOuterStringSerialize(ApiResponse<string> apiResponse, Guid requiredStringUuid, string body)
         {
         }
 
@@ -1096,8 +1110,9 @@ namespace Org.OpenAPITools.Api
         /// <param name="exception"></param>
         /// <param name="pathFormat"></param>
         /// <param name="path"></param>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
-        protected virtual void OnErrorFakeOuterStringSerialize(Exception exception, string pathFormat, string path, string body)
+        protected virtual void OnErrorFakeOuterStringSerialize(Exception exception, string pathFormat, string path, Guid requiredStringUuid, string body)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
         }
@@ -1106,16 +1121,19 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="string"/></returns>
-        public async Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = null, System.Threading.CancellationToken? cancellationToken = null)
+        public async Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = null, System.Threading.CancellationToken? cancellationToken = null)
         {
             UriBuilder uriBuilder = new UriBuilder();
 
             try
             {
-                body = OnFakeOuterStringSerialize(body);
+                var validatedParameters = OnFakeOuterStringSerialize(requiredStringUuid, body);
+                requiredStringUuid = validatedParameters.Item1;
+                body = validatedParameters.Item2;
 
                 using (HttpRequestMessage request = new HttpRequestMessage())
                 {
@@ -1124,6 +1142,12 @@ namespace Org.OpenAPITools.Api
                     uriBuilder.Scheme = ClientUtils.SCHEME;
                     uriBuilder.Path = ClientUtils.CONTEXT_PATH + "/fake/outer/string";
 
+                    System.Collections.Specialized.NameValueCollection parseQueryString = System.Web.HttpUtility.ParseQueryString(string.Empty);
+
+                    parseQueryString["required_string_uuid"] = Uri.EscapeDataString(requiredStringUuid.ToString());
+                    
+                    uriBuilder.Query = parseQueryString.ToString();
+
                     request.Content = (body as object) is System.IO.Stream stream
                         ? request.Content = new StreamContent(stream)
                         : request.Content = new StringContent(JsonSerializer.Serialize(body, _jsonSerializerOptions));
@@ -1165,7 +1189,7 @@ namespace Org.OpenAPITools.Api
                         if (apiResponse.IsSuccessStatusCode)
                         {
                             apiResponse.Content = JsonSerializer.Deserialize<string>(apiResponse.RawContent, _jsonSerializerOptions);
-                            AfterFakeOuterStringSerialize(apiResponse, body);
+                            AfterFakeOuterStringSerialize(apiResponse, requiredStringUuid, body);
                         }
 
                         return apiResponse;
@@ -1174,7 +1198,7 @@ namespace Org.OpenAPITools.Api
             }
             catch(Exception e)
             {
-                OnErrorFakeOuterStringSerialize(e, "/fake/outer/string", uriBuilder.Path, body);
+                OnErrorFakeOuterStringSerialize(e, "/fake/outer/string", uriBuilder.Path, requiredStringUuid, body);
                 throw;
             }
         }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 16a13ec3d17..a2c31499e85 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-net6.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -34,12 +34,16 @@ namespace Org.OpenAPITools.Model
         /// <param name="dateTime">dateTime</param>
         /// <param name="map">map</param>
         /// <param name="uuid">uuid</param>
+        /// <param name="uuidWithPattern">uuidWithPattern</param>
         [JsonConstructor]
-        public MixedPropertiesAndAdditionalPropertiesClass(DateTime dateTime, Dictionary<string, Animal> map, Guid uuid)
+        public MixedPropertiesAndAdditionalPropertiesClass(DateTime dateTime, Dictionary<string, Animal> map, Guid uuid, Guid uuidWithPattern)
         {
 #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
 #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
 
+            if (uuidWithPattern == null)
+                throw new ArgumentNullException("uuidWithPattern is a required property for MixedPropertiesAndAdditionalPropertiesClass and cannot be null.");
+
             if (uuid == null)
                 throw new ArgumentNullException("uuid is a required property for MixedPropertiesAndAdditionalPropertiesClass and cannot be null.");
 
@@ -55,6 +59,7 @@ namespace Org.OpenAPITools.Model
             DateTime = dateTime;
             Map = map;
             Uuid = uuid;
+            UuidWithPattern = uuidWithPattern;
         }
 
         /// <summary>
@@ -75,6 +80,12 @@ namespace Org.OpenAPITools.Model
         [JsonPropertyName("uuid")]
         public Guid Uuid { get; set; }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [JsonPropertyName("uuid_with_pattern")]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets additional properties
         /// </summary>
@@ -92,6 +103,7 @@ namespace Org.OpenAPITools.Model
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  AdditionalProperties: ").Append(AdditionalProperties).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
@@ -103,6 +115,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
@@ -132,6 +151,7 @@ namespace Org.OpenAPITools.Model
             DateTime dateTime = default;
             Dictionary<string, Animal> map = default;
             Guid uuid = default;
+            Guid uuidWithPattern = default;
 
             while (utf8JsonReader.Read())
             {
@@ -157,13 +177,16 @@ namespace Org.OpenAPITools.Model
                         case "uuid":
                             uuid = utf8JsonReader.GetGuid();
                             break;
+                        case "uuid_with_pattern":
+                            uuidWithPattern = utf8JsonReader.GetGuid();
+                            break;
                         default:
                             break;
                     }
                 }
             }
 
-            return new MixedPropertiesAndAdditionalPropertiesClass(dateTime, map, uuid);
+            return new MixedPropertiesAndAdditionalPropertiesClass(dateTime, map, uuid, uuidWithPattern);
         }
 
         /// <summary>
@@ -182,6 +205,7 @@ namespace Org.OpenAPITools.Model
             writer.WritePropertyName("map");
             JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);
             writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
+            writer.WriteString("uuid_with_pattern", mixedPropertiesAndAdditionalPropertiesClass.UuidWithPattern);
 
             writer.WriteEndObject();
         }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/docs/apis/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/docs/apis/FakeApi.md
index b815f20b5a0..1b47e75a7dd 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/docs/apis/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/docs/apis/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
index 0bac85a8e83..1bc0740add9 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/docs/models/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -7,6 +7,7 @@ Name | Type | Description | Notes
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
+**UuidWithPattern** | **Guid** |  | [optional] 
 
 [[Back to Model list]](../../README.md#documentation-for-models) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to README]](../../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
index 4c965120e69..0ba3c2103cf 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools.Test/Api/FakeApiTests.cs
@@ -100,8 +100,9 @@ namespace Org.OpenAPITools.Test.Api
         [Fact (Skip = "not implemented")]
         public async Task FakeOuterStringSerializeAsyncTest()
         {
+            Guid requiredStringUuid = default;
             string body = default;
-            var response = await _instance.FakeOuterStringSerializeAsync(body);
+            var response = await _instance.FakeOuterStringSerializeAsync(requiredStringUuid, body);
             Assert.IsType<string>(response);
         }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/FakeApi.cs
index c017ba3eccb..8c66c497f52 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -128,10 +128,11 @@ namespace Org.OpenAPITools.IApi
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task&lt;ApiResponse&lt;string&gt;&gt;</returns>
-        Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = null, System.Threading.CancellationToken? cancellationToken = null);
+        Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = null, System.Threading.CancellationToken? cancellationToken = null);
 
         /// <summary>
         /// 
@@ -140,10 +141,11 @@ namespace Org.OpenAPITools.IApi
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse&lt;string&gt;</returns>
-        Task<string> FakeOuterStringSerializeAsync(string body = null, System.Threading.CancellationToken? cancellationToken = null);
+        Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = null, System.Threading.CancellationToken? cancellationToken = null);
 
         /// <summary>
         /// Array of Enums
@@ -1056,12 +1058,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="string"/>&gt;</returns>
-        public async Task<string> FakeOuterStringSerializeAsync(string body = null, System.Threading.CancellationToken? cancellationToken = null)
+        public async Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = null, System.Threading.CancellationToken? cancellationToken = null)
         {
-            ApiResponse<string> result = await FakeOuterStringSerializeWithHttpInfoAsync(body, cancellationToken).ConfigureAwait(false);
+            ApiResponse<string> result = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, cancellationToken).ConfigureAwait(false);
 
             #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
             if (result.Content == null)
@@ -1074,19 +1077,30 @@ namespace Org.OpenAPITools.Api
         /// <summary>
         /// Validates the request parameters
         /// </summary>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
         /// <returns></returns>
-        protected virtual string OnFakeOuterStringSerialize(string body)
+        protected virtual (Guid, string) OnFakeOuterStringSerialize(Guid requiredStringUuid, string body)
         {
-            return body;
+            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+
+            if (requiredStringUuid == null)
+                throw new ArgumentNullException(nameof(requiredStringUuid));
+
+            #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
+            #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
+
+            return (requiredStringUuid, body);
         }
 
         /// <summary>
         /// Processes the server response
         /// </summary>
         /// <param name="apiResponse"></param>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
-        protected virtual void AfterFakeOuterStringSerialize(ApiResponse<string> apiResponse, string body)
+        protected virtual void AfterFakeOuterStringSerialize(ApiResponse<string> apiResponse, Guid requiredStringUuid, string body)
         {
         }
 
@@ -1096,8 +1110,9 @@ namespace Org.OpenAPITools.Api
         /// <param name="exception"></param>
         /// <param name="pathFormat"></param>
         /// <param name="path"></param>
+        /// <param name="requiredStringUuid"></param>
         /// <param name="body"></param>
-        protected virtual void OnErrorFakeOuterStringSerialize(Exception exception, string pathFormat, string path, string body)
+        protected virtual void OnErrorFakeOuterStringSerialize(Exception exception, string pathFormat, string path, Guid requiredStringUuid, string body)
         {
             Logger.LogError(exception, "An error occurred while sending the request to the server.");
         }
@@ -1106,16 +1121,19 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns><see cref="Task"/>&lt;<see cref="ApiResponse{T}"/>&gt; where T : <see cref="string"/></returns>
-        public async Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = null, System.Threading.CancellationToken? cancellationToken = null)
+        public async Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = null, System.Threading.CancellationToken? cancellationToken = null)
         {
             UriBuilder uriBuilder = new UriBuilder();
 
             try
             {
-                body = OnFakeOuterStringSerialize(body);
+                var validatedParameters = OnFakeOuterStringSerialize(requiredStringUuid, body);
+                requiredStringUuid = validatedParameters.Item1;
+                body = validatedParameters.Item2;
 
                 using (HttpRequestMessage request = new HttpRequestMessage())
                 {
@@ -1124,6 +1142,12 @@ namespace Org.OpenAPITools.Api
                     uriBuilder.Scheme = ClientUtils.SCHEME;
                     uriBuilder.Path = ClientUtils.CONTEXT_PATH + "/fake/outer/string";
 
+                    System.Collections.Specialized.NameValueCollection parseQueryString = System.Web.HttpUtility.ParseQueryString(string.Empty);
+
+                    parseQueryString["required_string_uuid"] = Uri.EscapeDataString(requiredStringUuid.ToString());
+                    
+                    uriBuilder.Query = parseQueryString.ToString();
+
                     request.Content = (body as object) is System.IO.Stream stream
                         ? request.Content = new StreamContent(stream)
                         : request.Content = new StringContent(JsonSerializer.Serialize(body, _jsonSerializerOptions));
@@ -1165,7 +1189,7 @@ namespace Org.OpenAPITools.Api
                         if (apiResponse.IsSuccessStatusCode)
                         {
                             apiResponse.Content = JsonSerializer.Deserialize<string>(apiResponse.RawContent, _jsonSerializerOptions);
-                            AfterFakeOuterStringSerialize(apiResponse, body);
+                            AfterFakeOuterStringSerialize(apiResponse, requiredStringUuid, body);
                         }
 
                         return apiResponse;
@@ -1174,7 +1198,7 @@ namespace Org.OpenAPITools.Api
             }
             catch(Exception e)
             {
-                OnErrorFakeOuterStringSerialize(e, "/fake/outer/string", uriBuilder.Path, body);
+                OnErrorFakeOuterStringSerialize(e, "/fake/outer/string", uriBuilder.Path, requiredStringUuid, body);
                 throw;
             }
         }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 16a13ec3d17..a2c31499e85 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-generichost-netstandard2.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -34,12 +34,16 @@ namespace Org.OpenAPITools.Model
         /// <param name="dateTime">dateTime</param>
         /// <param name="map">map</param>
         /// <param name="uuid">uuid</param>
+        /// <param name="uuidWithPattern">uuidWithPattern</param>
         [JsonConstructor]
-        public MixedPropertiesAndAdditionalPropertiesClass(DateTime dateTime, Dictionary<string, Animal> map, Guid uuid)
+        public MixedPropertiesAndAdditionalPropertiesClass(DateTime dateTime, Dictionary<string, Animal> map, Guid uuid, Guid uuidWithPattern)
         {
 #pragma warning disable CS0472 // The result of the expression is always the same since a value of this type is never equal to 'null'
 #pragma warning disable CS8073 // The result of the expression is always the same since a value of this type is never equal to 'null'
 
+            if (uuidWithPattern == null)
+                throw new ArgumentNullException("uuidWithPattern is a required property for MixedPropertiesAndAdditionalPropertiesClass and cannot be null.");
+
             if (uuid == null)
                 throw new ArgumentNullException("uuid is a required property for MixedPropertiesAndAdditionalPropertiesClass and cannot be null.");
 
@@ -55,6 +59,7 @@ namespace Org.OpenAPITools.Model
             DateTime = dateTime;
             Map = map;
             Uuid = uuid;
+            UuidWithPattern = uuidWithPattern;
         }
 
         /// <summary>
@@ -75,6 +80,12 @@ namespace Org.OpenAPITools.Model
         [JsonPropertyName("uuid")]
         public Guid Uuid { get; set; }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [JsonPropertyName("uuid_with_pattern")]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets additional properties
         /// </summary>
@@ -92,6 +103,7 @@ namespace Org.OpenAPITools.Model
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  AdditionalProperties: ").Append(AdditionalProperties).Append("\n");
             sb.Append("}\n");
             return sb.ToString();
@@ -103,6 +115,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
@@ -132,6 +151,7 @@ namespace Org.OpenAPITools.Model
             DateTime dateTime = default;
             Dictionary<string, Animal> map = default;
             Guid uuid = default;
+            Guid uuidWithPattern = default;
 
             while (utf8JsonReader.Read())
             {
@@ -157,13 +177,16 @@ namespace Org.OpenAPITools.Model
                         case "uuid":
                             uuid = utf8JsonReader.GetGuid();
                             break;
+                        case "uuid_with_pattern":
+                            uuidWithPattern = utf8JsonReader.GetGuid();
+                            break;
                         default:
                             break;
                     }
                 }
             }
 
-            return new MixedPropertiesAndAdditionalPropertiesClass(dateTime, map, uuid);
+            return new MixedPropertiesAndAdditionalPropertiesClass(dateTime, map, uuid, uuidWithPattern);
         }
 
         /// <summary>
@@ -182,6 +205,7 @@ namespace Org.OpenAPITools.Model
             writer.WritePropertyName("map");
             JsonSerializer.Serialize(writer, mixedPropertiesAndAdditionalPropertiesClass.Map, jsonSerializerOptions);
             writer.WriteString("uuid", mixedPropertiesAndAdditionalPropertiesClass.Uuid);
+            writer.WriteString("uuid_with_pattern", mixedPropertiesAndAdditionalPropertiesClass.UuidWithPattern);
 
             writer.WriteEndObject();
         }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/FakeApi.md
index 3f38af8889e..b46f71aeb7e 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/FakeApi.md
@@ -389,7 +389,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string body = null)
 
 
 
@@ -416,11 +416,12 @@ namespace Example
             HttpClient httpClient = new HttpClient();
             HttpClientHandler httpClientHandler = new HttpClientHandler();
             var apiInstance = new FakeApi(httpClient, config, httpClientHandler);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -440,7 +441,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -457,6 +458,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/MixedPropertiesAndAdditionalPropertiesClass.md
index 5f57db957d7..050210a3e37 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -4,6 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
+**UuidWithPattern** | **Guid** |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Api/FakeApi.cs
index 542c9dadd54..575bee123ae 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -113,9 +113,10 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <returns>string</returns>
-        string FakeOuterStringSerialize(string body = default(string));
+        string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string));
 
         /// <summary>
         /// 
@@ -124,9 +125,10 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <returns>ApiResponse of string</returns>
-        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string));
+        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string));
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -491,10 +493,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
 
         /// <summary>
         /// 
@@ -503,10 +506,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -1442,11 +1446,12 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <returns>string</returns>
-        public string FakeOuterStringSerialize(string body = default(string))
+        public string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string))
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(body);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
             return localVarResponse.Data;
         }
 
@@ -1454,9 +1459,10 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <returns>ApiResponse of string</returns>
-        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string))
+        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string))
         {
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
@@ -1475,6 +1481,7 @@ namespace Org.OpenAPITools.Api
             var localVarAccept = Org.OpenAPITools.Client.ClientUtils.SelectHeaderAccept(_accepts);
             if (localVarAccept != null) localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
 
@@ -1494,12 +1501,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(body, cancellationToken).ConfigureAwait(false);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, cancellationToken).ConfigureAwait(false);
             return localVarResponse.Data;
         }
 
@@ -1507,10 +1515,11 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
 
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
@@ -1531,6 +1540,7 @@ namespace Org.OpenAPITools.Api
             var localVarAccept = Org.OpenAPITools.Client.ClientUtils.SelectHeaderAccept(_accepts);
             if (localVarAccept != null) localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 22690e54091..ab33594b0e2 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -36,17 +36,25 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Initializes a new instance of the <see cref="MixedPropertiesAndAdditionalPropertiesClass" /> class.
         /// </summary>
+        /// <param name="uuidWithPattern">uuidWithPattern.</param>
         /// <param name="uuid">uuid.</param>
         /// <param name="dateTime">dateTime.</param>
         /// <param name="map">map.</param>
-        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
+        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuidWithPattern = default(Guid), Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
         {
+            this.UuidWithPattern = uuidWithPattern;
             this.Uuid = uuid;
             this.DateTime = dateTime;
             this.Map = map;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [DataMember(Name = "uuid_with_pattern", EmitDefaultValue = false)]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets Uuid
         /// </summary>
@@ -79,6 +87,7 @@ namespace Org.OpenAPITools.Model
         {
             StringBuilder sb = new StringBuilder();
             sb.Append("class MixedPropertiesAndAdditionalPropertiesClass {\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
@@ -125,6 +134,10 @@ namespace Org.OpenAPITools.Model
             unchecked // Overflow is fine, just wrap
             {
                 int hashCode = 41;
+                if (this.UuidWithPattern != null)
+                {
+                    hashCode = (hashCode * 59) + this.UuidWithPattern.GetHashCode();
+                }
                 if (this.Uuid != null)
                 {
                     hashCode = (hashCode * 59) + this.Uuid.GetHashCode();
@@ -152,6 +165,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/FakeApi.md
index 212d1d35c49..4b5bf803c4e 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/MixedPropertiesAndAdditionalPropertiesClass.md
index 5f57db957d7..050210a3e37 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -4,6 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
+**UuidWithPattern** | **Guid** |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/FakeApi.cs
index 5991b7f0b78..ca68e330338 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -121,10 +121,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0);
+        string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
 
         /// <summary>
         /// 
@@ -133,10 +134,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0);
+        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -529,11 +531,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
 
         /// <summary>
         /// 
@@ -542,11 +545,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -1509,12 +1513,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        public string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0)
+        public string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(body);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
             return localVarResponse.Data;
         }
 
@@ -1522,10 +1527,11 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0)
+        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
@@ -1550,6 +1556,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
@@ -1574,13 +1581,14 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(body, operationIndex, cancellationToken).ConfigureAwait(false);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, operationIndex, cancellationToken).ConfigureAwait(false);
             return localVarResponse.Data;
         }
 
@@ -1588,11 +1596,12 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
 
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
@@ -1618,6 +1627,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 3225727af37..2a0e96d6bc0 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -35,17 +35,25 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Initializes a new instance of the <see cref="MixedPropertiesAndAdditionalPropertiesClass" /> class.
         /// </summary>
+        /// <param name="uuidWithPattern">uuidWithPattern.</param>
         /// <param name="uuid">uuid.</param>
         /// <param name="dateTime">dateTime.</param>
         /// <param name="map">map.</param>
-        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
+        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuidWithPattern = default(Guid), Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
         {
+            this.UuidWithPattern = uuidWithPattern;
             this.Uuid = uuid;
             this.DateTime = dateTime;
             this.Map = map;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [DataMember(Name = "uuid_with_pattern", EmitDefaultValue = false)]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets Uuid
         /// </summary>
@@ -78,6 +86,7 @@ namespace Org.OpenAPITools.Model
         {
             StringBuilder sb = new StringBuilder();
             sb.Append("class MixedPropertiesAndAdditionalPropertiesClass {\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
@@ -124,6 +133,10 @@ namespace Org.OpenAPITools.Model
             unchecked // Overflow is fine, just wrap
             {
                 int hashCode = 41;
+                if (this.UuidWithPattern != null)
+                {
+                    hashCode = (hashCode * 59) + this.UuidWithPattern.GetHashCode();
+                }
                 if (this.Uuid != null)
                 {
                     hashCode = (hashCode * 59) + this.Uuid.GetHashCode();
@@ -151,6 +164,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/docs/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/docs/FakeApi.md
index 212d1d35c49..4b5bf803c4e 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/docs/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/docs/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/docs/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/docs/MixedPropertiesAndAdditionalPropertiesClass.md
index 5f57db957d7..050210a3e37 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/docs/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -4,6 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
+**UuidWithPattern** | **Guid** |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/src/Org.OpenAPITools/Api/FakeApi.cs
index 5991b7f0b78..ca68e330338 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -121,10 +121,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0);
+        string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
 
         /// <summary>
         /// 
@@ -133,10 +134,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0);
+        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -529,11 +531,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
 
         /// <summary>
         /// 
@@ -542,11 +545,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -1509,12 +1513,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        public string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0)
+        public string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(body);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
             return localVarResponse.Data;
         }
 
@@ -1522,10 +1527,11 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0)
+        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
@@ -1550,6 +1556,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
@@ -1574,13 +1581,14 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(body, operationIndex, cancellationToken).ConfigureAwait(false);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, operationIndex, cancellationToken).ConfigureAwait(false);
             return localVarResponse.Data;
         }
 
@@ -1588,11 +1596,12 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
 
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
@@ -1618,6 +1627,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 3225727af37..2a0e96d6bc0 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net48/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -35,17 +35,25 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Initializes a new instance of the <see cref="MixedPropertiesAndAdditionalPropertiesClass" /> class.
         /// </summary>
+        /// <param name="uuidWithPattern">uuidWithPattern.</param>
         /// <param name="uuid">uuid.</param>
         /// <param name="dateTime">dateTime.</param>
         /// <param name="map">map.</param>
-        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
+        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuidWithPattern = default(Guid), Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
         {
+            this.UuidWithPattern = uuidWithPattern;
             this.Uuid = uuid;
             this.DateTime = dateTime;
             this.Map = map;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [DataMember(Name = "uuid_with_pattern", EmitDefaultValue = false)]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets Uuid
         /// </summary>
@@ -78,6 +86,7 @@ namespace Org.OpenAPITools.Model
         {
             StringBuilder sb = new StringBuilder();
             sb.Append("class MixedPropertiesAndAdditionalPropertiesClass {\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
@@ -124,6 +133,10 @@ namespace Org.OpenAPITools.Model
             unchecked // Overflow is fine, just wrap
             {
                 int hashCode = 41;
+                if (this.UuidWithPattern != null)
+                {
+                    hashCode = (hashCode * 59) + this.UuidWithPattern.GetHashCode();
+                }
                 if (this.Uuid != null)
                 {
                     hashCode = (hashCode * 59) + this.Uuid.GetHashCode();
@@ -151,6 +164,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/FakeApi.md
index 2651845104a..17aae1affb8 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string? body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string? body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string? | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string?** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/MixedPropertiesAndAdditionalPropertiesClass.md
index 5f57db957d7..050210a3e37 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -4,6 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
+**UuidWithPattern** | **Guid** |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/FakeApi.cs
index e0829629cc2..16240126ca9 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -121,10 +121,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        string FakeOuterStringSerialize(string? body = default(string?), int operationIndex = 0);
+        string FakeOuterStringSerialize(Guid requiredStringUuid, string? body = default(string?), int operationIndex = 0);
 
         /// <summary>
         /// 
@@ -133,10 +134,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string? body = default(string?), int operationIndex = 0);
+        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string? body = default(string?), int operationIndex = 0);
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -529,11 +531,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string? body = default(string?), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string? body = default(string?), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
 
         /// <summary>
         /// 
@@ -542,11 +545,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string? body = default(string?), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string? body = default(string?), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -1509,12 +1513,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        public string FakeOuterStringSerialize(string? body = default(string?), int operationIndex = 0)
+        public string FakeOuterStringSerialize(Guid requiredStringUuid, string? body = default(string?), int operationIndex = 0)
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(body);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
             return localVarResponse.Data;
         }
 
@@ -1522,10 +1527,11 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string? body = default(string?), int operationIndex = 0)
+        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string? body = default(string?), int operationIndex = 0)
         {
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
@@ -1550,6 +1556,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
@@ -1574,13 +1581,14 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string? body = default(string?), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string? body = default(string?), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(body, operationIndex, cancellationToken).ConfigureAwait(false);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, operationIndex, cancellationToken).ConfigureAwait(false);
             return localVarResponse.Data;
         }
 
@@ -1588,11 +1596,12 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string? body = default(string?), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string? body = default(string?), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
 
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
@@ -1618,6 +1627,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 3225727af37..2a0e96d6bc0 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -35,17 +35,25 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Initializes a new instance of the <see cref="MixedPropertiesAndAdditionalPropertiesClass" /> class.
         /// </summary>
+        /// <param name="uuidWithPattern">uuidWithPattern.</param>
         /// <param name="uuid">uuid.</param>
         /// <param name="dateTime">dateTime.</param>
         /// <param name="map">map.</param>
-        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
+        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuidWithPattern = default(Guid), Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
         {
+            this.UuidWithPattern = uuidWithPattern;
             this.Uuid = uuid;
             this.DateTime = dateTime;
             this.Map = map;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [DataMember(Name = "uuid_with_pattern", EmitDefaultValue = false)]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets Uuid
         /// </summary>
@@ -78,6 +86,7 @@ namespace Org.OpenAPITools.Model
         {
             StringBuilder sb = new StringBuilder();
             sb.Append("class MixedPropertiesAndAdditionalPropertiesClass {\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
@@ -124,6 +133,10 @@ namespace Org.OpenAPITools.Model
             unchecked // Overflow is fine, just wrap
             {
                 int hashCode = 41;
+                if (this.UuidWithPattern != null)
+                {
+                    hashCode = (hashCode * 59) + this.UuidWithPattern.GetHashCode();
+                }
                 if (this.Uuid != null)
                 {
                     hashCode = (hashCode * 59) + this.Uuid.GetHashCode();
@@ -151,6 +164,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/FakeApi.md
index 212d1d35c49..4b5bf803c4e 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/MixedPropertiesAndAdditionalPropertiesClass.md
index 5f57db957d7..050210a3e37 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -4,6 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
+**UuidWithPattern** | **Guid** |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
index 5991b7f0b78..ca68e330338 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -121,10 +121,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0);
+        string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
 
         /// <summary>
         /// 
@@ -133,10 +134,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0);
+        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -529,11 +531,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
 
         /// <summary>
         /// 
@@ -542,11 +545,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -1509,12 +1513,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        public string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0)
+        public string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(body);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
             return localVarResponse.Data;
         }
 
@@ -1522,10 +1527,11 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0)
+        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
@@ -1550,6 +1556,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
@@ -1574,13 +1581,14 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(body, operationIndex, cancellationToken).ConfigureAwait(false);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, operationIndex, cancellationToken).ConfigureAwait(false);
             return localVarResponse.Data;
         }
 
@@ -1588,11 +1596,12 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
 
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
@@ -1618,6 +1627,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 3225727af37..2a0e96d6bc0 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -35,17 +35,25 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Initializes a new instance of the <see cref="MixedPropertiesAndAdditionalPropertiesClass" /> class.
         /// </summary>
+        /// <param name="uuidWithPattern">uuidWithPattern.</param>
         /// <param name="uuid">uuid.</param>
         /// <param name="dateTime">dateTime.</param>
         /// <param name="map">map.</param>
-        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
+        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuidWithPattern = default(Guid), Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
         {
+            this.UuidWithPattern = uuidWithPattern;
             this.Uuid = uuid;
             this.DateTime = dateTime;
             this.Map = map;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [DataMember(Name = "uuid_with_pattern", EmitDefaultValue = false)]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets Uuid
         /// </summary>
@@ -78,6 +86,7 @@ namespace Org.OpenAPITools.Model
         {
             StringBuilder sb = new StringBuilder();
             sb.Append("class MixedPropertiesAndAdditionalPropertiesClass {\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
@@ -124,6 +133,10 @@ namespace Org.OpenAPITools.Model
             unchecked // Overflow is fine, just wrap
             {
                 int hashCode = 41;
+                if (this.UuidWithPattern != null)
+                {
+                    hashCode = (hashCode * 59) + this.UuidWithPattern.GetHashCode();
+                }
                 if (this.Uuid != null)
                 {
                     hashCode = (hashCode * 59) + this.Uuid.GetHashCode();
@@ -151,6 +164,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/FakeApi.md b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/FakeApi.md
index 212d1d35c49..4b5bf803c4e 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/FakeApi.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/FakeApi.md
@@ -373,7 +373,7 @@ No authorization required
 
 <a name="fakeouterstringserialize"></a>
 # **FakeOuterStringSerialize**
-> string FakeOuterStringSerialize (string body = null)
+> string FakeOuterStringSerialize (Guid requiredStringUuid, string body = null)
 
 
 
@@ -396,11 +396,12 @@ namespace Example
             Configuration config = new Configuration();
             config.BasePath = "http://petstore.swagger.io:80/v2";
             var apiInstance = new FakeApi(config);
+            var requiredStringUuid = "requiredStringUuid_example";  // Guid | Required UUID String
             var body = "body_example";  // string | Input string as post body (optional) 
 
             try
             {
-                string result = apiInstance.FakeOuterStringSerialize(body);
+                string result = apiInstance.FakeOuterStringSerialize(requiredStringUuid, body);
                 Debug.WriteLine(result);
             }
             catch (ApiException  e)
@@ -420,7 +421,7 @@ This returns an ApiResponse object which contains the response data, status code
 ```csharp
 try
 {
-    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(body);
+    ApiResponse<string> response = apiInstance.FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
     Debug.Write("Status Code: " + response.StatusCode);
     Debug.Write("Response Headers: " + response.Headers);
     Debug.Write("Response Body: " + response.Data);
@@ -437,6 +438,7 @@ catch (ApiException e)
 
 | Name | Type | Description | Notes |
 |------|------|-------------|-------|
+| **requiredStringUuid** | **Guid** | Required UUID String |  |
 | **body** | **string** | Input string as post body | [optional]  |
 
 ### Return type
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/MixedPropertiesAndAdditionalPropertiesClass.md
index 5f57db957d7..050210a3e37 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -4,6 +4,7 @@
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
+**UuidWithPattern** | **Guid** |  | [optional] 
 **Uuid** | **Guid** |  | [optional] 
 **DateTime** | **DateTime** |  | [optional] 
 **Map** | [**Dictionary&lt;string, Animal&gt;**](Animal.md) |  | [optional] 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/FakeApi.cs
index 5991b7f0b78..ca68e330338 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -121,10 +121,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0);
+        string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
 
         /// <summary>
         /// 
@@ -133,10 +134,11 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0);
+        ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0);
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -529,11 +531,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
 
         /// <summary>
         /// 
@@ -542,11 +545,12 @@ namespace Org.OpenAPITools.Api
         /// Test serialization of outer string types
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
+        System.Threading.Tasks.Task<ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken));
         /// <summary>
         /// Array of Enums
         /// </summary>
@@ -1509,12 +1513,13 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>string</returns>
-        public string FakeOuterStringSerialize(string body = default(string), int operationIndex = 0)
+        public string FakeOuterStringSerialize(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(body);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = FakeOuterStringSerializeWithHttpInfo(requiredStringUuid, body);
             return localVarResponse.Data;
         }
 
@@ -1522,10 +1527,11 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <returns>ApiResponse of string</returns>
-        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(string body = default(string), int operationIndex = 0)
+        public Org.OpenAPITools.Client.ApiResponse<string> FakeOuterStringSerializeWithHttpInfo(Guid requiredStringUuid, string body = default(string), int operationIndex = 0)
         {
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
 
@@ -1550,6 +1556,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
@@ -1574,13 +1581,14 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of string</returns>
-        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<string> FakeOuterStringSerializeAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
-            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(body, operationIndex, cancellationToken).ConfigureAwait(false);
+            Org.OpenAPITools.Client.ApiResponse<string> localVarResponse = await FakeOuterStringSerializeWithHttpInfoAsync(requiredStringUuid, body, operationIndex, cancellationToken).ConfigureAwait(false);
             return localVarResponse.Data;
         }
 
@@ -1588,11 +1596,12 @@ namespace Org.OpenAPITools.Api
         ///  Test serialization of outer string types
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringUuid">Required UUID String</param>
         /// <param name="body">Input string as post body (optional)</param>
         /// <param name="operationIndex">Index associated with the operation.</param>
         /// <param name="cancellationToken">Cancellation Token to cancel the request.</param>
         /// <returns>Task of ApiResponse (string)</returns>
-        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
+        public async System.Threading.Tasks.Task<Org.OpenAPITools.Client.ApiResponse<string>> FakeOuterStringSerializeWithHttpInfoAsync(Guid requiredStringUuid, string body = default(string), int operationIndex = 0, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken))
         {
 
             Org.OpenAPITools.Client.RequestOptions localVarRequestOptions = new Org.OpenAPITools.Client.RequestOptions();
@@ -1618,6 +1627,7 @@ namespace Org.OpenAPITools.Api
                 localVarRequestOptions.HeaderParameters.Add("Accept", localVarAccept);
             }
 
+            localVarRequestOptions.QueryParameters.Add(Org.OpenAPITools.Client.ClientUtils.ParameterToMultiMap("", "required_string_uuid", requiredStringUuid));
             localVarRequestOptions.Data = body;
 
             localVarRequestOptions.Operation = "FakeApi.FakeOuterStringSerialize";
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 44fc73ca3a9..9fd3973afb8 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -35,16 +35,24 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Initializes a new instance of the <see cref="MixedPropertiesAndAdditionalPropertiesClass" /> class.
         /// </summary>
+        /// <param name="uuidWithPattern">uuidWithPattern.</param>
         /// <param name="uuid">uuid.</param>
         /// <param name="dateTime">dateTime.</param>
         /// <param name="map">map.</param>
-        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
+        public MixedPropertiesAndAdditionalPropertiesClass(Guid uuidWithPattern = default(Guid), Guid uuid = default(Guid), DateTime dateTime = default(DateTime), Dictionary<string, Animal> map = default(Dictionary<string, Animal>))
         {
+            this.UuidWithPattern = uuidWithPattern;
             this.Uuid = uuid;
             this.DateTime = dateTime;
             this.Map = map;
         }
 
+        /// <summary>
+        /// Gets or Sets UuidWithPattern
+        /// </summary>
+        [DataMember(Name = "uuid_with_pattern", EmitDefaultValue = false)]
+        public Guid UuidWithPattern { get; set; }
+
         /// <summary>
         /// Gets or Sets Uuid
         /// </summary>
@@ -71,6 +79,7 @@ namespace Org.OpenAPITools.Model
         {
             StringBuilder sb = new StringBuilder();
             sb.Append("class MixedPropertiesAndAdditionalPropertiesClass {\n");
+            sb.Append("  UuidWithPattern: ").Append(UuidWithPattern).Append("\n");
             sb.Append("  Uuid: ").Append(Uuid).Append("\n");
             sb.Append("  DateTime: ").Append(DateTime).Append("\n");
             sb.Append("  Map: ").Append(Map).Append("\n");
@@ -116,6 +125,10 @@ namespace Org.OpenAPITools.Model
             unchecked // Overflow is fine, just wrap
             {
                 int hashCode = 41;
+                if (this.UuidWithPattern != null)
+                {
+                    hashCode = (hashCode * 59) + this.UuidWithPattern.GetHashCode();
+                }
                 if (this.Uuid != null)
                 {
                     hashCode = (hashCode * 59) + this.Uuid.GetHashCode();
@@ -139,6 +152,13 @@ namespace Org.OpenAPITools.Model
         /// <returns>Validation Result</returns>
         public IEnumerable<System.ComponentModel.DataAnnotations.ValidationResult> Validate(ValidationContext validationContext)
         {
+            // UuidWithPattern (Guid) pattern
+            Regex regexUuidWithPattern = new Regex(@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}", RegexOptions.CultureInvariant);
+            if (false == regexUuidWithPattern.Match(this.UuidWithPattern.ToString()).Success)
+            {
+                yield return new System.ComponentModel.DataAnnotations.ValidationResult("Invalid value for UuidWithPattern, must match a pattern of " + regexUuidWithPattern, new [] { "UuidWithPattern" });
+            }
+
             yield break;
         }
     }