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

​

//https://stackoverflow.com/questions/63621028/inherit-attribute-when-implementing-abstract-base-field-c-sharp

​

    public abstract class Base

    {

        [JsonIgnore]

        public abstract IComparable SortValue { get; }

    }

​

    public class Derived : Base

    {

        public int VoteCount { get; set; }

​

        // Desire: inherited JsonIgnore attribute

        public override IComparable SortValue => VoteCount;

    }

​

    class TestClass

    {

        public static void Test()

        {

            var derived = new Derived { VoteCount = 101 };

            var json1 = JsonSerializer.Serialize(derived, typeof(Derived));

            Console.WriteLine(json1); // {"VoteCount":101,"SortValue":{}}

            var json2 = JsonSerializer.Serialize(derived, typeof(Base));

            Console.WriteLine(json2); //{}

        }   

    }

​

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

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

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

                return assemblyPath[netCoreAppIndex + 1];

            return null;

        }

    }

​