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 Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

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

​

//https://stackoverflow.com/questions/60443818/json-net-not-serializing-decimals-the-same-way-twice

​

    [JsonObject]

    public class Test : IEnumerable<IItem>

    {

        [JsonProperty(ItemConverterType = typeof(TestItemJsonConverter))]

        protected List<IItem> _items;

​

        public Test() { }

​

        [JsonConstructor]

        public Test(IEnumerable<IItem> o)

        {

            _items = o == null ? new List<IItem>() : new List<IItem>(o);

        }

​

        public decimal Total { get; set; }

​

        IEnumerator IEnumerable.GetEnumerator()

        {

            return _items.GetEnumerator();

        }

​

        IEnumerator<IItem> IEnumerable<IItem>.GetEnumerator()

        {

            return _items.GetEnumerator();

        }

    }

​

    public interface IItem

    {

        string ItemName { get; }

    }

​

    public class Item1 : IItem

    {

        public Item1() { }

        public Item1(decimal fee) { Fee = fee; }

​

        public string ItemName { get { return "Item1"; } }

​

        public virtual decimal Fee { get; set; }

    }

​

    public class TestItemJsonConverter : JsonConverter

    {

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

        {

            object result = null;

​

            var old = reader.FloatParseHandling;

            try

            {

                reader.FloatParseHandling = FloatParseHandling.Decimal;

                JObject jObj = JObject.Load(reader);

                string itemTypeID = jObj["ItemName"].Value<string>();

​

                //NOTE: My real implementation doesn't have hard coded strings or types here.

                //See the code block below for actual implementation.

                if (itemTypeID == "Item1")

                    result = jObj.ToObject(typeof(Item1), serializer);

            }

            finally

            {

                reader.FloatParseHandling = old;

            }

​

            return result;

        }

​

        public override bool CanConvert(Type objectType) { return (objectType == typeof(IItem)); }

​

        public override bool CanWrite { get { return false; } }

​

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) { throw new NotImplementedException(); }

    }

​

​

    class TestClass

    {

        public static void Test()

        {

            Test test1 = new Test(new List<Item1> { new Item1(9.00m), new Item1(24.0000m) })

            {

                Total = 33.0000m

            };

​

            string json = JsonConvert.SerializeObject(test1, Formatting.Indented);

            Console.WriteLine(json);

            Console.WriteLine();

​

            Test test1Clone = JsonConvert.DeserializeObject<Test>(json);

            string json2 = JsonConvert.SerializeObject(test1Clone, Formatting.Indented);

            Console.WriteLine(json2);

            Assert.IsTrue(json2 == 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;

            }

        }

    }

​