[C#] Fix oneOf derserialization with additional properties (#8057)

* fix oneOf derserializaoneOf deserialization with additonal prop

* fix tests due to better handlding of additional prop

modules/openapi-generator/src/main/resources/csharp-netcore/AbstractOpenAPISchema.mustache

@@ -28,6 +28,23 @@ namespace {{packageName}}.{{modelPackage}}
             }
         };
 
+        /// <summary>
+        ///  Custom JSON serializer for objects with additional properties
+        /// </summary>
+        static public readonly JsonSerializerSettings AdditionalPropertiesSerializerSettings = new JsonSerializerSettings
+        {
+            // OpenAPI generated types generally hide default constructors.
+            ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor,
+            MissingMemberHandling = MissingMemberHandling.Ignore,
+            ContractResolver = new DefaultContractResolver
+            {
+                NamingStrategy = new CamelCaseNamingStrategy
+                {
+                    OverrideSpecifiedNames = false
+                }
+            }
+        };
+
         /// <summary>
         /// Gets or Sets the actual instance
         /// </summary>

modules/openapi-generator/src/main/resources/csharp-netcore/modelOneOf.mustache

@@ -112,7 +112,12 @@
             {
                 {{#mappedModels}}
                 case "{{{mappingName}}}":
+                    new{{classname}} = new {{classname}}(JsonConvert.DeserializeObject<{{{modelName}}}>(jsonString, {{classname}}.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (new{{{classname}}}.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         new{{classname}} = new {{classname}}(JsonConvert.DeserializeObject<{{{modelName}}}>(jsonString, {{classname}}.SerializerSettings));
+                    }
                     return new{{classname}};
                 {{/mappedModels}}
                 default:
@@ -127,8 +132,13 @@
             {{#oneOf}}
 
             try
+            {
+                new{{classname}} = new {{classname}}(JsonConvert.DeserializeObject<{{{.}}}>(jsonString, {{classname}}.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (new{{{classname}}}.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     new{{classname}} = new {{classname}}(JsonConvert.DeserializeObject<{{{.}}}>(jsonString, {{classname}}.SerializerSettings));
+                }
                 matchedTypes.Add("{{{.}}}");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs

@@ -36,6 +36,23 @@ namespace Org.OpenAPITools.Model
             }
         };
 
+        /// <summary>
+        ///  Custom JSON serializer for objects with additional properties
+        /// </summary>
+        static public readonly JsonSerializerSettings AdditionalPropertiesSerializerSettings = new JsonSerializerSettings
+        {
+            // OpenAPI generated types generally hide default constructors.
+            ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor,
+            MissingMemberHandling = MissingMemberHandling.Ignore,
+            ContractResolver = new DefaultContractResolver
+            {
+                NamingStrategy = new CamelCaseNamingStrategy
+                {
+                    OverrideSpecifiedNames = false
+                }
+            }
+        };
+
         /// <summary>
         /// Gets or Sets the actual instance
         /// </summary>

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/Fruit.cs

@@ -146,8 +146,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Apple>(jsonString, Fruit.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruit.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruit = new Fruit(JsonConvert.DeserializeObject<Apple>(jsonString, Fruit.SerializerSettings));
+                }
                 matchedTypes.Add("Apple");
                 match++;
             }
@@ -158,8 +163,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Banana>(jsonString, Fruit.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruit.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruit = new Fruit(JsonConvert.DeserializeObject<Banana>(jsonString, Fruit.SerializerSettings));
+                }
                 matchedTypes.Add("Banana");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/FruitReq.cs

@@ -155,8 +155,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<AppleReq>(jsonString, FruitReq.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruitReq.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruitReq = new FruitReq(JsonConvert.DeserializeObject<AppleReq>(jsonString, FruitReq.SerializerSettings));
+                }
                 matchedTypes.Add("AppleReq");
                 match++;
             }
@@ -167,8 +172,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<BananaReq>(jsonString, FruitReq.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruitReq.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruitReq = new FruitReq(JsonConvert.DeserializeObject<BananaReq>(jsonString, FruitReq.SerializerSettings));
+                }
                 matchedTypes.Add("BananaReq");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/Mammal.cs

@@ -174,13 +174,28 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "Pig":
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.SerializerSettings));
+                    }
                     return newMammal;
                 case "whale":
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.SerializerSettings));
+                    }
                     return newMammal;
                 case "zebra":
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.SerializerSettings));
+                    }
                     return newMammal;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Mammal. Possible values: Pig whale zebra", discriminatorValue));
@@ -191,8 +206,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Pig");
                 match++;
             }
@@ -203,8 +223,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Whale");
                 match++;
             }
@@ -215,8 +240,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Zebra");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/NullableShape.cs

@@ -157,10 +157,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
+                    newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.SerializerSettings));
+                    }
                     return newNullableShape;
                 case "Triangle":
+                    newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.SerializerSettings));
+                    }
                     return newNullableShape;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for NullableShape. Possible values: Quadrilateral Triangle", discriminatorValue));
@@ -171,8 +181,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -183,8 +198,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/Pig.cs

@@ -148,10 +148,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "BasquePig":
+                    newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newPig.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.SerializerSettings));
+                    }
                     return newPig;
                 case "DanishPig":
+                    newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newPig.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.SerializerSettings));
+                    }
                     return newPig;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Pig. Possible values: BasquePig DanishPig", discriminatorValue));
@@ -162,8 +172,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newPig.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.SerializerSettings));
+                }
                 matchedTypes.Add("BasquePig");
                 match++;
             }
@@ -174,8 +189,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newPig.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.SerializerSettings));
+                }
                 matchedTypes.Add("DanishPig");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/Quadrilateral.cs

@@ -148,10 +148,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "ComplexQuadrilateral":
+                    newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                    }
                     return newQuadrilateral;
                 case "SimpleQuadrilateral":
+                    newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                    }
                     return newQuadrilateral;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Quadrilateral. Possible values: ComplexQuadrilateral SimpleQuadrilateral", discriminatorValue));
@@ -162,8 +172,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                }
                 matchedTypes.Add("ComplexQuadrilateral");
                 match++;
             }
@@ -174,8 +189,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                }
                 matchedTypes.Add("SimpleQuadrilateral");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/Shape.cs

@@ -148,10 +148,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
+                    newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newShape.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.SerializerSettings));
+                    }
                     return newShape;
                 case "Triangle":
+                    newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newShape.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.SerializerSettings));
+                    }
                     return newShape;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Shape. Possible values: Quadrilateral Triangle", discriminatorValue));
@@ -162,8 +172,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -174,8 +189,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/ShapeOrNull.cs

@@ -157,10 +157,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
+                    newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.SerializerSettings));
+                    }
                     return newShapeOrNull;
                 case "Triangle":
+                    newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.SerializerSettings));
+                    }
                     return newShapeOrNull;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for ShapeOrNull. Possible values: Quadrilateral Triangle", discriminatorValue));
@@ -171,8 +181,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -183,8 +198,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/Triangle.cs

@@ -174,13 +174,28 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "EquilateralTriangle":
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.SerializerSettings));
+                    }
                     return newTriangle;
                 case "IsoscelesTriangle":
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.SerializerSettings));
+                    }
                     return newTriangle;
                 case "ScaleneTriangle":
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.SerializerSettings));
+                    }
                     return newTriangle;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Triangle. Possible values: EquilateralTriangle IsoscelesTriangle ScaleneTriangle", discriminatorValue));
@@ -191,8 +206,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("EquilateralTriangle");
                 match++;
             }
@@ -203,8 +223,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("IsoscelesTriangle");
                 match++;
             }
@@ -215,8 +240,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("ScaleneTriangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/JSONComposedSchemaTests.cs

@@ -86,7 +86,8 @@ namespace Org.OpenAPITools.Test
             Assert.IsType<Banana>(f3.ActualInstance);
 
             Fruit f4 = Fruit.FromJson("{\"origin\":\"Japan\"}");
-            Assert.IsType<Apple>(f4.ActualInstance);
+            // since banana allows additional properties, it will apple's JSON payload as well
+            Assert.IsType<Banana>(f4.ActualInstance);
 
             // test custom deserializer
             Fruit f5 = JsonConvert.DeserializeObject<Fruit>("{\"lengthCm\":98}");
@@ -117,5 +118,18 @@ namespace Org.OpenAPITools.Test
             Cat c = JsonConvert.DeserializeObject<Cat>("{\"className\":\"cat\",\"bar\":\"from json bar\"}");
             Assert.Equal("from json bar", c.AdditionalProperties["bar"]);
         }
+
+        /// <summary>
+        /// Test additonal properties
+        /// </summary>
+        [Fact]
+        public void TestAdditionalProperties()
+        {
+            Foo f = new Foo();
+
+            Assert.NotNull(f.GetType().GetProperty("AdditionalProperties"));
+            Assert.Null(f.GetType().GetProperty("unknown_property"));
+
+        }
     }
 }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs

@@ -36,6 +36,23 @@ namespace Org.OpenAPITools.Model
             }
         };
 
+        /// <summary>
+        ///  Custom JSON serializer for objects with additional properties
+        /// </summary>
+        static public readonly JsonSerializerSettings AdditionalPropertiesSerializerSettings = new JsonSerializerSettings
+        {
+            // OpenAPI generated types generally hide default constructors.
+            ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor,
+            MissingMemberHandling = MissingMemberHandling.Ignore,
+            ContractResolver = new DefaultContractResolver
+            {
+                NamingStrategy = new CamelCaseNamingStrategy
+                {
+                    OverrideSpecifiedNames = false
+                }
+            }
+        };
+
         /// <summary>
         /// Gets or Sets the actual instance
         /// </summary>

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Fruit.cs

@@ -146,8 +146,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Apple>(jsonString, Fruit.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruit.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruit = new Fruit(JsonConvert.DeserializeObject<Apple>(jsonString, Fruit.SerializerSettings));
+                }
                 matchedTypes.Add("Apple");
                 match++;
             }
@@ -158,8 +163,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Banana>(jsonString, Fruit.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruit.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruit = new Fruit(JsonConvert.DeserializeObject<Banana>(jsonString, Fruit.SerializerSettings));
+                }
                 matchedTypes.Add("Banana");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/FruitReq.cs

@@ -155,8 +155,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<AppleReq>(jsonString, FruitReq.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruitReq.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruitReq = new FruitReq(JsonConvert.DeserializeObject<AppleReq>(jsonString, FruitReq.SerializerSettings));
+                }
                 matchedTypes.Add("AppleReq");
                 match++;
             }
@@ -167,8 +172,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<BananaReq>(jsonString, FruitReq.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruitReq.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruitReq = new FruitReq(JsonConvert.DeserializeObject<BananaReq>(jsonString, FruitReq.SerializerSettings));
+                }
                 matchedTypes.Add("BananaReq");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Mammal.cs

@@ -174,13 +174,28 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "Pig":
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.SerializerSettings));
+                    }
                     return newMammal;
                 case "whale":
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.SerializerSettings));
+                    }
                     return newMammal;
                 case "zebra":
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.SerializerSettings));
+                    }
                     return newMammal;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Mammal. Possible values: Pig whale zebra", discriminatorValue));
@@ -191,8 +206,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Pig");
                 match++;
             }
@@ -203,8 +223,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Whale");
                 match++;
             }
@@ -215,8 +240,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Zebra");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/NullableShape.cs

@@ -157,10 +157,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
+                    newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.SerializerSettings));
+                    }
                     return newNullableShape;
                 case "Triangle":
+                    newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.SerializerSettings));
+                    }
                     return newNullableShape;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for NullableShape. Possible values: Quadrilateral Triangle", discriminatorValue));
@@ -171,8 +181,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -183,8 +198,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Pig.cs

@@ -148,10 +148,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "BasquePig":
+                    newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newPig.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.SerializerSettings));
+                    }
                     return newPig;
                 case "DanishPig":
+                    newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newPig.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.SerializerSettings));
+                    }
                     return newPig;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Pig. Possible values: BasquePig DanishPig", discriminatorValue));
@@ -162,8 +172,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newPig.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.SerializerSettings));
+                }
                 matchedTypes.Add("BasquePig");
                 match++;
             }
@@ -174,8 +189,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newPig.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.SerializerSettings));
+                }
                 matchedTypes.Add("DanishPig");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Quadrilateral.cs

@@ -148,10 +148,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "ComplexQuadrilateral":
+                    newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                    }
                     return newQuadrilateral;
                 case "SimpleQuadrilateral":
+                    newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                    }
                     return newQuadrilateral;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Quadrilateral. Possible values: ComplexQuadrilateral SimpleQuadrilateral", discriminatorValue));
@@ -162,8 +172,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                }
                 matchedTypes.Add("ComplexQuadrilateral");
                 match++;
             }
@@ -174,8 +189,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                }
                 matchedTypes.Add("SimpleQuadrilateral");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Shape.cs

@@ -148,10 +148,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
+                    newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newShape.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.SerializerSettings));
+                    }
                     return newShape;
                 case "Triangle":
+                    newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newShape.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.SerializerSettings));
+                    }
                     return newShape;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Shape. Possible values: Quadrilateral Triangle", discriminatorValue));
@@ -162,8 +172,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -174,8 +189,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ShapeOrNull.cs

@@ -157,10 +157,20 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
+                    newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.SerializerSettings));
+                    }
                     return newShapeOrNull;
                 case "Triangle":
+                    newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.SerializerSettings));
+                    }
                     return newShapeOrNull;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for ShapeOrNull. Possible values: Quadrilateral Triangle", discriminatorValue));
@@ -171,8 +181,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -183,8 +198,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Triangle.cs

@@ -174,13 +174,28 @@ namespace Org.OpenAPITools.Model
             switch (discriminatorValue)
             {
                 case "EquilateralTriangle":
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.SerializerSettings));
+                    }
                     return newTriangle;
                 case "IsoscelesTriangle":
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.SerializerSettings));
+                    }
                     return newTriangle;
                 case "ScaleneTriangle":
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                    // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                    if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
+                    {
                         newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.SerializerSettings));
+                    }
                     return newTriangle;
                 default:
                     System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Triangle. Possible values: EquilateralTriangle IsoscelesTriangle ScaleneTriangle", discriminatorValue));
@@ -191,8 +206,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("EquilateralTriangle");
                 match++;
             }
@@ -203,8 +223,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("IsoscelesTriangle");
                 match++;
             }
@@ -215,8 +240,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("ScaleneTriangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs

@@ -36,6 +36,23 @@ namespace Org.OpenAPITools.Model
             }
         };
 
+        /// <summary>
+        ///  Custom JSON serializer for objects with additional properties
+        /// </summary>
+        static public readonly JsonSerializerSettings AdditionalPropertiesSerializerSettings = new JsonSerializerSettings
+        {
+            // OpenAPI generated types generally hide default constructors.
+            ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor,
+            MissingMemberHandling = MissingMemberHandling.Ignore,
+            ContractResolver = new DefaultContractResolver
+            {
+                NamingStrategy = new CamelCaseNamingStrategy
+                {
+                    OverrideSpecifiedNames = false
+                }
+            }
+        };
+
         /// <summary>
         /// Gets or Sets the actual instance
         /// </summary>

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Fruit.cs

@@ -146,8 +146,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Apple>(jsonString, Fruit.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruit.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruit = new Fruit(JsonConvert.DeserializeObject<Apple>(jsonString, Fruit.SerializerSettings));
+                }
                 matchedTypes.Add("Apple");
                 match++;
             }
@@ -158,8 +163,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Banana>(jsonString, Fruit.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruit.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruit = new Fruit(JsonConvert.DeserializeObject<Banana>(jsonString, Fruit.SerializerSettings));
+                }
                 matchedTypes.Add("Banana");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/FruitReq.cs

@@ -155,8 +155,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<AppleReq>(jsonString, FruitReq.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruitReq.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruitReq = new FruitReq(JsonConvert.DeserializeObject<AppleReq>(jsonString, FruitReq.SerializerSettings));
+                }
                 matchedTypes.Add("AppleReq");
                 match++;
             }
@@ -167,8 +172,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<BananaReq>(jsonString, FruitReq.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newFruitReq.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newFruitReq = new FruitReq(JsonConvert.DeserializeObject<BananaReq>(jsonString, FruitReq.SerializerSettings));
+                }
                 matchedTypes.Add("BananaReq");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Mammal.cs

@@ -173,8 +173,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Pig");
                 match++;
             }
@@ -185,8 +190,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Whale");
                 match++;
             }
@@ -197,8 +207,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newMammal.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.SerializerSettings));
+                }
                 matchedTypes.Add("Zebra");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/NullableShape.cs

@@ -156,8 +156,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -168,8 +173,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newNullableShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Pig.cs

@@ -147,8 +147,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newPig.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.SerializerSettings));
+                }
                 matchedTypes.Add("BasquePig");
                 match++;
             }
@@ -159,8 +164,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newPig.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.SerializerSettings));
+                }
                 matchedTypes.Add("DanishPig");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Quadrilateral.cs

@@ -147,8 +147,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                }
                 matchedTypes.Add("ComplexQuadrilateral");
                 match++;
             }
@@ -159,8 +164,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newQuadrilateral.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
+                }
                 matchedTypes.Add("SimpleQuadrilateral");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Shape.cs

@@ -147,8 +147,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -159,8 +164,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShape.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ShapeOrNull.cs

@@ -156,8 +156,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.SerializerSettings));
+                }
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
@@ -168,8 +173,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newShapeOrNull.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.SerializerSettings));
+                }
                 matchedTypes.Add("Triangle");
                 match++;
             }

samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Triangle.cs

@@ -173,8 +173,13 @@ namespace Org.OpenAPITools.Model
             List<string> matchedTypes = new List<string>();
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("EquilateralTriangle");
                 match++;
             }
@@ -185,8 +190,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("IsoscelesTriangle");
                 match++;
             }
@@ -197,8 +207,13 @@ namespace Org.OpenAPITools.Model
             }
 
             try
+            {
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.AdditionalPropertiesSerializerSettings));
+                // if it does not contains "AdditionalProperties", use SerializerSettings to deserialize
+                if (newTriangle.GetType().GetProperty("AdditionalProperties") == null)
                 {
                     newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.SerializerSettings));
+                }
                 matchedTypes.Add("ScaleneTriangle");
                 match++;
             }