With a simple class/interface like this
public interface IThing { string Name { get; set; } } public class Thing : IThing { public int Id { get; se
You can use conditional serialization. Take a look at this link. Basicly, you need to implement the IContractResolver interface, overload the ShouldSerialize method and pass your resolver to the constructor of the Json Serializer.
IContractResolver
ShouldSerialize