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

​

using JToken = Newtonsoft.Json.Linq.JToken;

​

//https://stackoverflow.com/questions/66750433/how-to-convert-json-array-to-collection-with-system-text-json

​

    class CustomStringToRoleConverter : JsonConverter<ISet<User.Role>> {

        public override ISet<User.Role> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) =>

            JsonSerializer.Deserialize<List<string>>(ref reader, options)

                .Select(s => Enum.Parse<User.Role>(s))

                .ToHashSet(); // Or use a SortedSet if you prefer

​

        public override void Write(Utf8JsonWriter writer, ISet<User.Role> roles, JsonSerializerOptions options) =>

            JsonSerializer.Serialize(writer, roles.Select(r => r.ToString()), options);

    }

​

    public class User

    {

        public enum Role

        {

            Admin,

            User,

        }

        public ISet<User.Role> Roles { get; set; } = new HashSet<User.Role>();

    }

​

    class TestClass

    {

        public static void Test()

        {

            var json = GetJson();

            Console.WriteLine(json);

            var options = new JsonSerializerOptions

            {

                Converters = { new CustomStringToRoleConverter() },

                WriteIndented = true,

            };

            var model = JsonSerializer.Deserialize<User>(json, options);

            model.Dump();

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

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

            Console.WriteLine(json2);

            // Assert we round-tripped successfully

            Assert.IsTrue(JToken.DeepEquals(JToken.Parse(json), JToken.Parse(json2)));

        }

        static string GetJson() => @"{""Roles"":[""Admin"",""User""]}";

    }

​

    public class Program

    {

        public static void Main()

        {

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

            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;

            }

        }

        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.Location.Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);

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

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

                return assemblyPath[netCoreAppIndex + 1];

            return "";

        }

    }

​