using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

using System.Threading;

using System.Collections.ObjectModel;

using System.Reflection;

using System.ComponentModel;

using System.Globalization;

using System.Collections.Specialized;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;

​

​

    public interface ISubStuff

    {

        string Item { get; set; }

    }

    public class SubStuff : ISubStuff

    {

       public string Item { get; set; }

    }

    public interface IMainStuff

    {

        Dictionary<string, ISubStuff> SubStuff { get; set; }

    }

​

    public class MainStuff : IMainStuff

    { 

        [JsonProperty(ItemConverterType = typeof(TypeConverter<ISubStuff, SubStuff>))]

        public Dictionary<string, ISubStuff> SubStuff

        { 

            get; 

            set; 

        } 

    }

​

    public class TypeConverter<T, TSerialized> : CustomCreationConverter<T> 

        where TSerialized : T, new()

    {

        public override T Create(Type objectType)

        {

            return new TSerialized();

        }

    }

    public class Program

    {

        static void Test()

        {

            var root = new MainStuff

            {

                SubStuff = new Dictionary<string, ISubStuff>()

                {

                    { "key1", new SubStuff { Item = "hello 1" } },

                    { "key2", new SubStuff { Item = "hello 2" } },

                },

            };

            var json1 = JsonConvert.SerializeObject(root);

            Console.WriteLine(json1);

            var root2 = JsonConvert.DeserializeObject<MainStuff>(json1);

            var json2 = JsonConvert.SerializeObject(root2);

            Console.WriteLine(json2);

        }

        public static void Main()

        {

            try

            {

                Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​

    public class UnrelatedSubStuff : ISubStuff

    {

       public string Item { get; set; }

    }   

​

​