title: Can I pass an interface based object to an MVC 4 WebApi POST?
body: <p>I want to have an API as such:</p>
  
  <pre><code>public class RelayController : ApiController
  {
      // POST api/values
      public void Post([FromBody]IDataRelayPackage package)
      {
          MessageQueue queue = new MessageQueue(".\\private$\\DataRelay");
          queue.Send(package);
          queue.Close();
      }
  }
  </code></pre>
  
  <p>I'm getting a null value for 'package' so I'm wondering what might be going wrong. My only thoughts are that the default <code>JSON</code> serializer can't handle this, but I'm unclear how to fix it. </p>