ApiController.cs

/**
 * Both of the below methods are valid actions in an ApiController, and both would result in the 
 * same response being sent to the client.
 **/

// GET api/strings
public IEnumerable<string> Get()
{
    return new string[] { "value1", "value2" };
}

// GET api/strings
public HttpResponseMessage Get()
{
    return Request.CreateResponse(HttpStatusCode.OK, new[] { "value1", "value2" });
}