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 Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

//     // https://stackoverflow.com/questions/46293907/create-custom-json-converter-using-newtonsoft-json-library-to-get-additional-dat

​

​

    class AbcDTO

    {

        public AbcDTO() { this.AdditionalData = new Dictionary<string, object>(); }

​

        public string Prop1 { get; set; }

        public string Prop2 { get; set; }

        //public List<AdditionalProperty> AdditionalData { get; set; }

​

        [JsonExtensionData]

        public Dictionary<string, object> AdditionalData { get; private set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var json = GetJson();

​

            var dto = JsonConvert.DeserializeObject<AbcDTO>(json);

​

            var json2 = JsonConvert.SerializeObject(dto, Formatting.Indented);

​

            Console.WriteLine(json2);

​

            // Assert all the values are primitives.

            Console.WriteLine(string.Format("Dictionary value types: {0}", String.Join(",", dto.AdditionalData.Values.Select(v => v == null ? "null" : v.GetType().ToString()))));

            Assert.IsTrue(!dto.AdditionalData.Values.OfType<JToken>().Any(), "Some values were of type JToken!");

            Console.WriteLine("No dictionary values were of type JToken.");

        }

​

        static string GetJson()

        {

            var json = @"{

    ""Prop1"": ""Val1"",

    ""Prop2"": ""Val2"",

    ""AdditionalProp3"": ""Val3"",

    ""AdditionalProp4"": ""Val4"",

    ""AdditionalProp5"": 1010101,

    ""AdditionalProp6"": true,

    ""AdditionalProp7"": null,

    ""AdditionalProp8"": ""2012-03-19T07:22Z"",

}

";

            return json;

        }

    }

​

    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;

            }

        }

    }

​

    public class AssertionFailedException : System.Exception

    {

        public AssertionFailedException() : base() { }

​

        public AssertionFailedException(string s) : base(s) { }

    }

​

    public static class Assert

    {

        public static void IsTrue(bool value)

        {

            IsTrue(value, "failed");

        }

​

        public static void IsTrue(bool value, string message)

        {

            if (value == false)

                throw new AssertionFailedException(message ?? "failed");

        }

    }

​