using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

using System.Text.Json;

using System.Text.Json.Serialization;

​

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

​

//https://stackoverflow.com/questions/75512547/using-a-custom-enum-json-converter

​

#nullable enable

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    public class CustomEnumConverter : JsonConverterFactory

    {

        public override bool CanConvert(Type typeToConvert) => typeToConvert.IsEnum; // Add anything additional here such as typeToConvert.IsEnumWithDescription() to check for description attributes.

​

        public override JsonConverter CreateConverter(Type typeToConvert, JsonSerializerOptions options) =>

            (JsonConverter)Activator.CreateInstance(typeof(CustomConverter<>).MakeGenericType(typeToConvert))!;

​

        class CustomConverter<T> : JsonConverter<T> where T : struct, Enum

        {

            public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) =>

                reader.GetString()!.GetEnumValue<T>()!;

​

            public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options) =>

                writer.WriteStringValue(value.GetDescription<T>());

        }

    }

​

    public static class EnumExtensions

    {

        const string prefix = "descriptions_";

        // These are for demonstrational purposes only.  You would want to replace these with your actual mapping logic.

        public static string GetDescription<TEnum>(this TEnum value) where TEnum : struct, Enum => prefix + value.ToString();

        public static TEnum GetEnumValue<TEnum>(this string value) where TEnum : struct, Enum => Enum.Parse<TEnum>(value.StartsWith(prefix) ? value.AsSpan().Slice(prefix.Length) : value.AsSpan(), true);

    }

​

    public enum SomeEnum

    {

        Foo,

        Bar,

    }

​

    public enum Enum2 : long

    {

        Foo2,

        Bar2,

    }

​

    public class Model

    {

        [JsonConverter(typeof(CustomEnumConverter))]

        public SomeEnum? SomeEnum { get; set; }

        public Enum2 Enum2 { get; set; }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var model = new Model { SomeEnum = SomeEnum.Bar, Enum2 = Enum2.Bar2 };

​

            var options = new JsonSerializerOptions

            {

                Converters = { new CustomEnumConverter() },

                WriteIndented = true

            };

​

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

            Console.WriteLine(json);

            var model2 = JsonSerializer.Deserialize<Model>(json, options);

            Assert.AreEqual(model.SomeEnum, model2?.SomeEnum);

            Assert.AreEqual(model.Enum2, model2?.Enum2);

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1}), {2}", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version, Environment.OSVersion);

            Console.WriteLine("System.Text.Json version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​