https://stackoverflow.com/questions/54341115/jobject-tostring-with-stringenumconverter-not-working

CSharp · Console

/Program.cs

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/54341115/jobject-tostring-with-stringenumconverter-not-working

	public enum ErrorCode 
	{
		A,
		B,
		C
	}

    class TestClass
    {
        public static void Test()
        {
			var response = JObject.FromObject(
				new
				{
					Error = new
					{
						Message = "Test",
						Code = ErrorCode.A
					}
				},
				JsonSerializer.CreateDefault(new JsonSerializerSettings { Converters = { new StringEnumConverter() } })
			)
			.ToString(Formatting.None);
			
			Console.WriteLine(response);
			
			// Now try serializing to JObject without StringEnumConverter.  Note that the value of 
			// Error.Code will be of type System.Int32
			var obj = JObject.FromObject(
				new
				{
					Error = new
					{
						Message = "Test",
						Code = ErrorCode.A
					}
				},
				JsonSerializer.CreateDefault(new JsonSerializerSettings {  })
			);	
			
			Console.WriteLine(obj.SelectToken("Error.Code"));
			Console.WriteLine(((JValue)obj.SelectToken("Error.Code")).Value.GetType());
			
			// Here's an example of using a JsonConverter that applies to primitives with ToString()
			var convertedJson = obj.ToString(Formatting.None, new PrefixingStringConverter("converter prefix:   "));
			Console.WriteLine(convertedJson);
		}
		
		static string GetJson()
		{
			var json = @"
";
			return json;
		}
	}

    public class PrefixingStringConverter : JsonConverter
    {
        // Taken from this answer https://stackoverflow.com/a/46797460/3744182
        // To https://stackoverflow.com/questions/46788778/how-to-deserialize-dodgy-json-with-improperly-quoted-strings-and-missing-brack
		readonly string prefix;
		
		public PrefixingStringConverter(string prefix)
		{
			this.prefix = prefix;
		}

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

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

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            var s = (string)value;
			writer.WriteValue(prefix + s);
        }
    }

	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;
			}
		}
	}