diff --git a/bin/utils/test_file_list.yaml b/bin/utils/test_file_list.yaml
index 3d7cf02ace5..d2d65e328f9 100644
--- a/bin/utils/test_file_list.yaml
+++ b/bin/utils/test_file_list.yaml
@@ -1,6 +1,6 @@
 ---
 # csharp-netcore test files and image for upload
 - filename: "samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs"
-  sha256: b74ef9eefa4b41fd3233e083fe2355babf25a77f9073d28e1aa81ae2e0a5f1d0
+  sha256: aceebba316148a2a803a15ef4e13bbd0b0a1b8d15006cd88adb9b39a620ee451
 - filename: "samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/linux-logo.png"
   sha256: 0a67c32728197e942b13bdda064b73793f12f5c795f1e5cf35a3adf69c973230
diff --git a/modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache b/modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache
index c1d025d7f03..1b5571eff72 100644
--- a/modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/csharp-netcore/ApiClient.mustache
@@ -472,6 +472,19 @@ namespace {{packageName}}.Client
                 response = client.Execute<T>(req);
             }
 
+            // if the response type is oneOf/anyOf, call FromJSON to deserialize the data
+            if (typeof({{{packageName}}}.{{modelPackage}}.AbstractOpenAPISchema).IsAssignableFrom(typeof(T)))
+            {
+                T instance = (T)Activator.CreateInstance(typeof(T));
+                MethodInfo method = typeof(T).GetMethod("FromJson");
+                method.Invoke(instance, new object[] { response.Content });
+                response.Data = instance;
+            }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
+
             InterceptResponse(req, response);
 
             var result = ToApiResponse(response);
@@ -583,6 +596,10 @@ namespace {{packageName}}.Client
                 method.Invoke(instance, new object[] { response.Content });
                 response.Data = instance;
             }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
 
             InterceptResponse(req, response);
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Client/ApiClient.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Client/ApiClient.cs
index 53e4ce7fd45..d70c53adbdb 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Client/ApiClient.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Client/ApiClient.cs
@@ -477,6 +477,19 @@ namespace Org.OpenAPITools.Client
                 response = client.Execute<T>(req);
             }
 
+            // if the response type is oneOf/anyOf, call FromJSON to deserialize the data
+            if (typeof(Org.OpenAPITools.Model.AbstractOpenAPISchema).IsAssignableFrom(typeof(T)))
+            {
+                T instance = (T)Activator.CreateInstance(typeof(T));
+                MethodInfo method = typeof(T).GetMethod("FromJson");
+                method.Invoke(instance, new object[] { response.Content });
+                response.Data = instance;
+            }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
+
             InterceptResponse(req, response);
 
             var result = ToApiResponse(response);
@@ -587,6 +600,10 @@ namespace Org.OpenAPITools.Client
                 method.Invoke(instance, new object[] { response.Content });
                 response.Data = instance;
             }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
 
             InterceptResponse(req, response);
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Client/ApiClient.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Client/ApiClient.cs
index 5c4b6465dbc..a78ae625eee 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Client/ApiClient.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Client/ApiClient.cs
@@ -477,6 +477,19 @@ namespace Org.OpenAPITools.Client
                 response = client.Execute<T>(req);
             }
 
+            // if the response type is oneOf/anyOf, call FromJSON to deserialize the data
+            if (typeof(Org.OpenAPITools.Model.AbstractOpenAPISchema).IsAssignableFrom(typeof(T)))
+            {
+                T instance = (T)Activator.CreateInstance(typeof(T));
+                MethodInfo method = typeof(T).GetMethod("FromJson");
+                method.Invoke(instance, new object[] { response.Content });
+                response.Data = instance;
+            }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
+
             InterceptResponse(req, response);
 
             var result = ToApiResponse(response);
@@ -587,6 +600,10 @@ namespace Org.OpenAPITools.Client
                 method.Invoke(instance, new object[] { response.Content });
                 response.Data = instance;
             }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
 
             InterceptResponse(req, response);
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs
index b3376d6045e..1ca767977f2 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/Api/PetApiTests.cs
@@ -199,6 +199,19 @@ namespace Org.OpenAPITools.Test
             Assert.Equal("sample category name2", response.Category.Name);
         }
 
+        /* a simple test for binary response. no longer in use.
+        [Fact]
+        public void TestGetByIdBinaryResponse()
+        {
+            PetApi petApi = new PetApi(c1);
+            Stream response = petApi.GetPetByIdBinaryResponse(petId);
+            Assert.IsType<System.IO.MemoryStream>(response);
+            StreamReader reader = new StreamReader(response);
+            // the following will fail for sure
+            //Assert.Equal("someting", reader.ReadToEnd());
+        }
+        */
+
         /// <summary>
         /// Test GetPetByIdWithHttpInfoAsync
         /// </summary>
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs
index 520896de7ea..020a2df2dc3 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Client/ApiClient.cs
@@ -476,6 +476,19 @@ namespace Org.OpenAPITools.Client
                 response = client.Execute<T>(req);
             }
 
+            // if the response type is oneOf/anyOf, call FromJSON to deserialize the data
+            if (typeof(Org.OpenAPITools.Model.AbstractOpenAPISchema).IsAssignableFrom(typeof(T)))
+            {
+                T instance = (T)Activator.CreateInstance(typeof(T));
+                MethodInfo method = typeof(T).GetMethod("FromJson");
+                method.Invoke(instance, new object[] { response.Content });
+                response.Data = instance;
+            }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
+
             InterceptResponse(req, response);
 
             var result = ToApiResponse(response);
@@ -586,6 +599,10 @@ namespace Org.OpenAPITools.Client
                 method.Invoke(instance, new object[] { response.Content });
                 response.Data = instance;
             }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
 
             InterceptResponse(req, response);
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs
index 53e4ce7fd45..d70c53adbdb 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Client/ApiClient.cs
@@ -477,6 +477,19 @@ namespace Org.OpenAPITools.Client
                 response = client.Execute<T>(req);
             }
 
+            // if the response type is oneOf/anyOf, call FromJSON to deserialize the data
+            if (typeof(Org.OpenAPITools.Model.AbstractOpenAPISchema).IsAssignableFrom(typeof(T)))
+            {
+                T instance = (T)Activator.CreateInstance(typeof(T));
+                MethodInfo method = typeof(T).GetMethod("FromJson");
+                method.Invoke(instance, new object[] { response.Content });
+                response.Data = instance;
+            }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
+
             InterceptResponse(req, response);
 
             var result = ToApiResponse(response);
@@ -587,6 +600,10 @@ namespace Org.OpenAPITools.Client
                 method.Invoke(instance, new object[] { response.Content });
                 response.Data = instance;
             }
+            else if (typeof(T).Name == "Stream") // for binary response
+            {
+                response.Data = (T)(object)new MemoryStream(response.RawBytes);
+            }
 
             InterceptResponse(req, response);