using System;

using System.Collections.Generic;

using Newtonsoft.Json;

using Newtonsoft.Json.Serialization;

using System.Reflection;

​

[AddJsonTypename]

public class Epsilon

{

    public Phi[] Tags { get; set; }

​

    public class Phi

    {

        public string Internal_Name { get; set; }

        public string Name { get; set; }

        public string[] Nutty { get; set; }

    }

}

​

public class Program

{

    public static void Main()

    {

        Epsilon ep = new Epsilon

        {

            Tags = new Epsilon.Phi[]

            {

                new Epsilon.Phi

                {

                    Internal_Name = "Some text"

                }

            }

        };

        Console.WriteLine(JsonConvert.SerializeObject(ep, new JsonSerializerSettings { ContractResolver = new AddJsonTypenameContractResolver() }));

    }

}

​

[AttributeUsage(AttributeTargets.Class| AttributeTargets.Interface, AllowMultiple = false, Inherited = false)]

public class AddJsonTypenameAttribute : Attribute

{

}

​

public class AddJsonTypenameContractResolver : DefaultContractResolver

{

    // As of 7.0.1, Json.NET suggests using a static instance for "stateless" contract resolvers, for performance reasons.

    // http://www.newtonsoft.com/json/help/html/ContractResolver.htm

    // http://www.newtonsoft.com/json/help/html/M_Newtonsoft_Json_Serialization_DefaultContractResolver__ctor_1.htm

    // "Use the parameterless constructor and cache instances of the contract resolver within your application for optimal performance."

    // See also https://stackoverflow.com/questions/33557737/does-json-net-cache-types-serialization-information

    static AddJsonTypenameContractResolver instance;

​

    // Explicit static constructor to tell C# compiler not to mark type as beforefieldinit

    static AddJsonTypenameContractResolver() { instance = new AddJsonTypenameContractResolver(); }

​

    public static AddJsonTypenameContractResolver Instance { get { return instance; } }

​

    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)

    {

        return base.CreateProperty(member, memberSerialization)

            .ApplyAddTypenameAttribute();

    }

​

    protected override JsonArrayContract CreateArrayContract(Type objectType)

    {

        return base.CreateArrayContract(objectType)

            .ApplyAddTypenameAttribute();

    }

}

​

public static class ContractResolverExtensions

{

    public static JsonProperty ApplyAddTypenameAttribute(this JsonProperty jsonProperty)

    {

        if (jsonProperty.TypeNameHandling == null)

        {

            if (jsonProperty.PropertyType.GetCustomAttribute<AddJsonTypenameAttribute>(false) != null)

            {

                jsonProperty.TypeNameHandling = TypeNameHandling.All;

            }

        }

        return jsonProperty;

    }

​

    public static JsonArrayContract ApplyAddTypenameAttribute(this JsonArrayContract contract)

    {

        if (contract.ItemTypeNameHandling == null)

        {

            if (contract.CollectionItemType.GetCustomAttribute<AddJsonTypenameAttribute>(false) != null)

            {

                contract.ItemTypeNameHandling = TypeNameHandling.All;

            }

        }

        return contract;

    }

}