using System;

using System.Collections;

using System.Collections.Generic;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        MyCaseRequest data = new MyCaseRequest()

        {

            Name = "TestAgre",

            ExpirationDateTime = "2016-07-14T00:00:00.000Z",

            Signatories = new List<SignatoryRequest>

            {

                new MyRequest() { Type = MyType.Comp, Id = "11111" },

                new MyRequest() { Type = MyType.Per, Id = "2222" }

            },

            Documents = new SortedList<string, ThingsRequest>()

            {

                {"0" , new ThingsRequest() { Name = "Test",  Description = "Short description about", Length = 4523 }},

                {"1" , new ThingsRequest() { Name = "Test1",  Description = "short description about", Length = 56986 }}

            }

        };

        JsonSerializerSettings settings = new JsonSerializerSettings();

        settings.Converters.Add(new DictionaryToValuesArrayConverter());

        settings.Formatting = Formatting.Indented;

        string json = JsonConvert.SerializeObject(data, settings);

        Console.WriteLine(json);

    }

}

​

class MyCaseRequest

{

    public string Name { get; set; }

    public string ExpirationDateTime { get; set; }

    public List<SignatoryRequest> Signatories { get; set; }

    public SortedList<string, ThingsRequest> Documents { get; set; }

}

​

class SignatoryRequest

{

}

​

class MyRequest : SignatoryRequest

{

    public MyType Type { get; set; }

    public string Id { get; set; }

}

​

enum MyType { Comp, Per }

​

class ThingsRequest

{

    public string Name { get; set; }

    public string Description { get; set; }

    public int Length { get; set; }

}

​

class DictionaryToValuesArrayConverter : JsonConverter

{

    public override bool CanConvert(Type objectType)

    {

        return typeof(IDictionary).IsAssignableFrom(objectType);

    }

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

    {

        IDictionary dict = (IDictionary)value;

        JArray array = JArray.FromObject(dict.Values);

        array.WriteTo(writer);

    }

    public override bool CanRead

    {

        get { return false; }

    }

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

    {

        throw new NotImplementedException();

    }

}

​