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 System.Collections.ObjectModel;

​

using System.Text.Json;

using System.Text.Json.Serialization;

​

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

​

//https://stackoverflow.com/questions/59498173/properties-of-extended-dictionary-wont-show-in-serialization

​

    internal class Translation : Dictionary<string, string>

    {

        public string Name { get; set; }

    }

​

    internal class TranslationConverter : JsonConverter<Translation>

    {

        internal class TranslationDTO

        {

            public string Name { get; set; }

​

            [JsonExtensionData]

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

        }

​

        public override Translation Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)

        {

            var dto = JsonSerializer.Deserialize<TranslationDTO>(ref reader, options);

            if (dto == null)

                return null;

            var translation = new Translation { Name = dto.Name };

            foreach (var p in dto.Data)

                translation.Add(p.Key, p.Value?.ToString());

            return translation;

        }

​

        public override void Write(Utf8JsonWriter writer, Translation value, JsonSerializerOptions options)

        {

            var dto = new TranslationDTO { Name = value.Name, Data = value.ToDictionary(p => p.Key, p => (object)p.Value) };

            JsonSerializer.Serialize(writer, dto, options);

        }

    }

​

    class TestClass

    {

        public static void Test()

        {

            TestSerialize();

            TestRoundTrip();

        }

​

        static void TestSerialize()

        {

            var translation = new Translation

            {

                Name = "donkey",

                ["key1"] = "value2",

                ["key2"] = "value2",

                ["key3"] = "value3",

            };

​

            var options = new JsonSerializerOptions

            {

                Converters = { new TranslationConverter() },

                PropertyNamingPolicy = JsonNamingPolicy.CamelCase,

                // Other options as required

                WriteIndented = true,

            };

​

            var json = JsonSerializer.Serialize(translation, options);

​

            Console.WriteLine("Serialized {0}", translation);

            Console.WriteLine(json);

        }

        public static void TestRoundTrip()

        {

            var json = GetJson();

            var options = new JsonSerializerOptions

            {

                Converters = { new TranslationConverter() },

                PropertyNamingPolicy = JsonNamingPolicy.CamelCase,

                // Other options as required

                WriteIndented = true,

            };

            var translation = JsonSerializer.Deserialize<Translation>(json, options);

​

            var json2 = JsonSerializer.Serialize(translation, options);

            Console.WriteLine("Re-serialized {0}", translation);

            Console.WriteLine(json2);

​

            Assert.IsTrue(translation.Name == "donkey");

        }   

        static string GetJson()

        {

            var json = @"{

  ""name"": ""donkey"",

  ""key1"": ""value1"",

  ""key2"": ""value2"",

  ""key3"": ""value3""

}

";

            return json;

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1})", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , GetNetCoreVersion());

            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 static string GetNetCoreVersion()

        {

            //https://techblog.dorogin.com/how-to-detect-net-core-version-in-runtime-ecd65ad695be

            //

            var assembly = typeof(System.Runtime.GCSettings).GetTypeInfo().Assembly;

            var assemblyPath = assembly.CodeBase.Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);

            int netCoreAppIndex = Array.IndexOf(assemblyPath, "Microsoft.NETCore.App");

            if (netCoreAppIndex > 0 && netCoreAppIndex < assemblyPath.Length - 2)

                return assemblyPath[netCoreAppIndex + 1];

            return null;

        }

    }

​