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 }); } 

Answer 2

This answer may come bit late but as of today WebApi 2 is already out and now it is easier to do what you want, you would just have to do:

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

and along the pipeline, it will be serialized to xml or json according to client's preferences (the Accept header). Hope this helps anyone stumbling upon this question