JsonNetCharConverter.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Linq;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace jnbug
{
	class MainClass
	{
		private static Encoding encoding = Encoding.UTF8;

		public static void Main(string[] args)
		{
			string path = DateTime.Now.ToString("ddHHmmss") + ".txt";

			var foo = new Foo();
			foo.Bar = new List<char>(new char[] {(char)56256 });
			var d = foo.AsDictionary();

			using (StreamWriter streamWriter = new StreamWriter(path, false, encoding))
			{
				using (JsonTextWriter jsonWriter = new JsonTextWriter(streamWriter))
				{
					JsonSerializer serializer = new JsonSerializer();
					serializer.Converters.Add(new CharConverter());

					serializer.Serialize(jsonWriter, foo);
					jsonWriter.Flush();
				}
			}

			using (StreamReader streamReader = new StreamReader(path, encoding, true))
			{
				using (JsonTextReader jsonReader = new JsonTextReader(streamReader))
				{
					JsonSerializer serializer = new JsonSerializer();
					serializer.Converters.Add(new CharConverter());

					var k = serializer.Deserialize<Foo>(jsonReader);

					foreach (var item in k.Bar)
					{
						Console.WriteLine((UInt16)item + " : " + item);
					}

					var d2 = k.AsDictionary();
					foreach (var item in d2)
					{
						Console.WriteLine(item.Key + " : " + item.Value);
					}
				}
			}
			// Output: 56256 = 65533
		}
	}

	public class Foo
	{
		//[JsonConverter(typeof(CharListConverter))]
		public List<char> Bar { get; set;}

		public IDictionary<char, UInt16> AsDictionary()
		{
			return Bar.ToDictionary(f => f, (f) => (UInt16)f);
		}
	}

	public class CharConverter : JsonConverter
	{
		public override bool CanConvert(Type objectType)
		{
			return objectType.Equals(typeof(char));
		}

		public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
		{
			var token = JToken.Load(reader);
			return (char)token.Value<UInt16>();
		}

		public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
		{
			char character = (char)value;
			writer.WriteValue(((UInt16)character));
		}
	}
}