C# HttpClient PostAsync turns 204 into 404

Question

Given this WebApi service:

[ActionName(\"KillPerson\")]
[HttpPost]
public void KillPerson([FromBody] long id)
{
    // Kill
}

And this HttpClie

Answer 1

Finally figured this out. Seems you get a choice of using either browser or client HTTP handling in Silverlight. When using browser HTTP handling a lot of stuff is unsupported - including various response codes and headers. Adding these lines before calling HttpClient fixed it:

WebRequest.RegisterPrefix("http://", WebRequestCreator.ClientHttp);
WebRequest.RegisterPrefix("https://", WebRequestCreator.ClientHttp);