using System;

using System.Globalization;

using Newtonsoft.Json;

using Newtonsoft.Json.Serialization;

using System.Reflection;

​

public class Program

{

    public class MyTypeContractResolver<T> : DefaultContractResolver

    {

        protected override JsonProperty CreateProperty(MemberInfo member,

                                                       MemberSerialization

                                                           memberSerialization)

        {

            var property = base.CreateProperty(member, memberSerialization);

​

            property.Ignored = false;

            property.ShouldSerialize = propInstance => property.DeclaringType != typeof (T) && property.PropertyName != nameof(ExceptionBase.Features);

            return property;

        }

    }

    [Flags]

    public enum ExceptionBaseFeatures

    {

        HasA = 1,

        HasB = 2,

        HasC = 4

    }

    public class ExceptionBase {

        [JsonIgnore]

        public virtual int A_ { get => throw new InvalidOperationException(); set => throw new InvalidOperationException(); }

        [JsonIgnore]

        public virtual int B_ { get => throw new InvalidOperationException(); set => throw new InvalidOperationException(); }

        [JsonIgnore]

        public virtual int C_ { get => throw new InvalidOperationException(); set => throw new InvalidOperationException(); }

        [JsonIgnore]

        public virtual ExceptionBaseFeatures Features { get; }

    }

    public class A : ExceptionBase

    {

        public override int A_ { get; set; }

        public override int B_ { get; set; }

        public override ExceptionBaseFeatures Features => ExceptionBaseFeatures.HasA | ExceptionBaseFeatures.HasB;

    }

    public class B : ExceptionBase

    {

        public override int B_ { get; set; }

        public override int C_ { get; set; }

        public override ExceptionBaseFeatures Features => ExceptionBaseFeatures.HasB | ExceptionBaseFeatures.HasC;

    }

    public static void Main()

    {

        var a = new A() {

            A_ = 1,

            B_ = 2

        };

        var b = new B() {

            B_ = 5,

            C_ = 6

        };

        Console.WriteLine(JsonConvert.SerializeObject(a, new JsonSerializerSettings {ContractResolver = new MyTypeContractResolver<ExceptionBase>()}));

        Console.WriteLine(JsonConvert.SerializeObject(b, new JsonSerializerSettings {ContractResolver = new MyTypeContractResolver<ExceptionBase>()}));

        Console.WriteLine(((ExceptionBase)a).C_);

    }

}