EnumJsonConverter.cs

public class EnumJsonConverter<TEnum, T> : JsonConverter<Enum<TEnum, T>>
   where TEnum : Enum<TEnum, T>
{
   public override void WriteJson(JsonWriter writer, Enum<TEnum, T> value, JsonSerializer serializer)
   {
      if (value == null)
      {
         writer.WriteNull();
      }
      else
      {
         serializer.Serialize(writer, value.Key);
      }
   }

   public override Enum<TEnum, T> ReadJson(JsonReader reader, Type objectType, Enum<TEnum, T> existingValue, bool hasExistingValue, JsonSerializer serializer)
   {
      if (reader.TokenType == JsonToken.Null)
         return null;

      var key = serializer.Deserialize<T>(reader);
      return Enum<TEnum, T>.Get(key);
   }
}