How to serialize object to json with type info using Newtonsoft.Json?

Question

I want to have a property with type name in JSON when I serialize objects of certain types. I wrote a converter:

public class TypeInfoConverter : JsonConverter {     private readonly IEnumerable<Type> _types;      public TypeInfoConverter(IEnumerable<Type> types) {         Contract.Requires(types != null);          _types = types;     }      public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {         var jObject = JObject.FromObject(value, serializer);         jObject.AddFirst(new JProperty("Type", value.GetType().Name));         jObject.WriteTo(writer);     }      public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) {         return serializer.Deserialize(reader, objectType);     }      public override bool CanConvert(Type objectType) {         return _types.Any(t => t.IsAssignableFrom(objectType));     } } 

But when I'm trying to serialize object I have an infinity recursion here: var jObject = JObject.FromObject(value, serializer); It is obvious because I use the same instance of JsonSerializer which was configured with that converter.

How to prevent using this converter, but I want to use other converters which configured for this serializer?

Types which I want to serialize:

public interface ITaskResult { }  public class UserHasRejectedOffer : ITaskResult {     public string Message { get; set; } }  public class UserHasFilledForm : ITaskResult {     public string FormValue1 { get; set; }      public string Formvalue2 { get; set; } }  ... 

Answer 1

var jsonSerializerSettings = new JsonSerializerSettings() {      TypeNameHandling = TypeNameHandling.All }; var json = JsonConvert.SerializeObject(instance, jsonSerializerSettings); 

http://james.newtonking.com/json/help/index.html?topic=html/SerializationSettings.htm

Answer 2

public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)      var converters = serializer.Converters.Where(x => !(x is TypeInfoConverter)).ToArray();      var jObject = JObject.FromObject(value);     jObject.AddFirst(new JProperty("Type", value.GetType().Name));     jObject.WriteTo(writer, converters); }