using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.Serialization.Formatters;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

using System.Globalization;

using System.Reflection;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

    //https://stackoverflow.com/questions/53401189/c-sharp-jsonconvert-using-the-default-converter-instead-of-the-custom-converter

    //https://stackoverflow.com/questions/53401189/c-sharp-jsonconvert-using-the-default-converter-instead-of-the-custom-converter

​

    public class ConverterDisablingContractResolver : DefaultContractResolver

    {

        readonly HashSet<Type> types;

​

        public ConverterDisablingContractResolver(IEnumerable<Type> types)

        {

            if (types == null)

                throw new ArgumentNullException();

            this.types = new HashSet<Type>(types);

        }

​

        bool ContainsType(Type type)

        {

            return types.Contains(type);

        }

​

        protected override JsonConverter ResolveContractConverter(Type objectType)

        {

            // This could be enhanced to deal with inheritance.  I.e. if TBase is in types and has a converter then

            // its converter should not be used for TDerived -- but if TDerived has its own converter then it should still be

            // used, so simply returning null for TDerived would be wrong.

            if (types.Contains(objectType))

                return null;

            return base.ResolveContractConverter(objectType);

        }

    }

​

    public interface IShape

    {

        string Value { get; set; }

    }

​

    [JsonConverter(typeof(TheShapeSerializer))]

    public class TheShape : IShape

    {

        public string Value { get; set; }

    }

​

    class TheShapeSerializer : JsonConverter

    {

        public override bool CanConvert(Type objectType)

        {

            throw new NotImplementedException();

        }

​

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

        {

            throw new NotImplementedException();

        }

​

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

        {

            throw new NotImplementedException();

        }

    }

​

    public class ShapeContainer

    {

        [JsonConverter(typeof(NoConverter))]

        public TheShape Shape { get; set; }

​

        [JsonProperty(ItemConverterType = typeof(NoConverter))]

        public List<TheShape> Shapes { get; set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var shape = new TheShape { Value = "my value" };

​

            TestShapeContainer(shape);

            TestContractResolver(shape);

​

            try

            {

                Console.WriteLine("Trying to directly serialize a {0}...", shape);

                JsonConvert.SerializeObject(shape);

                // Should not come here.

                Assert.IsTrue(false);

            }

            catch (NotImplementedException ex)

            {

                Console.WriteLine("   ...caught expected exception {0}", ex.Message);

            }

​

            Console.WriteLine("\nAll tests passed.");

        }

​

        static IContractResolver shapeResolver = new ConverterDisablingContractResolver(new[] { typeof(TheShape) });

​

        static void TestShapeContainer(TheShape shape)

        {

            var root = new ShapeContainer

            {

                Shape = shape,

                Shapes = new List<TheShape> { shape, shape },

            };

            var json = JsonConvert.SerializeObject(root);

            Console.WriteLine(json);

        }

​

        static void TestContractResolver(TheShape shape)

        {

            var root = new

            {

                Shape = shape,

                Shapes = new[] { shape, shape },

            };

​

            var settings = new JsonSerializerSettings

            {

                ContractResolver = shapeResolver,

            };

​

            var json = JsonConvert.SerializeObject(root, settings);

            Console.WriteLine(json);

        }

    }

​

    public class NoConverter : JsonConverter

    {

        // Taken from https://stackoverflow.com/questions/39738714/selectively-use-default-json-converter/39739105#39739105

        public override bool CanConvert(Type objectType)

        {

            // Note - not called when attached directly via [JsonConverter(typeof(NoConverter))]

            throw new NotImplementedException();

        }

​

        public override bool CanRead { get { return false; } }

​

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

        {

            throw new NotImplementedException();

        }

​

        public override bool CanWrite { get { return false; } }

​

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

        {

            throw new NotImplementedException();

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: " + Environment.Version);

            Console.WriteLine("Json.NET version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​