Returning anonymous types with Web API

Question

When using MVC, returning adhoc Json was easy.

return Json(new { Message = "Hello"});

I'm looking for this functionality with the new Web API.

public HttpResponseMessage<object> Test()
{    
   return new HttpResponseMessage<object>(new { Message = "Hello" }, HttpStatusCode.OK);
}

This throws an exception as the DataContractJsonSerializer can't handle anonymous types.

I have replaced this with this JsonNetFormatter based on Json.Net. This works if I use

 public object Test()
 {
    return new { Message = "Hello" };
 }

but I don't see the point of using Web API if I'm not returning HttpResponseMessage, I would be better off sticking with vanilla MVC. If I try and use:

public HttpResponseMessage<object> Test()
{
   return new HttpResponseMessage<object>(new { Message = "Hello" }, HttpStatusCode.OK);
}

It serializes the whole HttpResponseMessage.

Can anyone guide me to a solution where I can return anonymous types within a HttpResponseMessage?

Answer 1

This doesn't work in the Beta release, but it does in the latest bits (built from http://aspnetwebstack.codeplex.com), so it will likely be the way for RC. You can do

public HttpResponseMessage Get()
{
    return this.Request.CreateResponse(
        HttpStatusCode.OK,
        new { Message = "Hello", Value = 123 });
}