title: HOW? Controller return nothing/current view
body: <p>SHORT:<br>
  How do I make a controller return the current view or just simply do nothing?</p>
  
  <p>LONG:<br>
  I have a partial view where i've created an imageslider.
  It contains a link which sends a request to a controller to get the next image (using ajax).
  The controller fetches the next image, stores it in ViewData and sends back a partial view (the one above).
  <br><br>
  Now, what I do today is that when the controller reaches the last image it re-return the very same image (by refetching it), but still creates a new view, that is, the client/browser re-parses the "same" data.
  <br>
  This seems somewhat non-optimal.<br><br>
  What I'd like to do is that when controller reaches the last image it should simply do nothing.<br>
  If I return null then the view is updated with empty contents.<br>
  I want the view/client/browser to retain whatever it has and the controller to simply do nothing.</p>
  
  <pre><code>    [AcceptVerbs(HttpVerbs.Post)]
      public ActionResult GetNextImage(...)
      {
          if(Request.IsAjaxRequest())
          {
              if(CURRENT_IMAGE != LAST_IMAGE)
              {
                  Image image = GetNextImage(...);
                  var partialViewResult = new PartialViewResult();
                  partialViewResult.ViewName = "ImageSlide";
                  partialViewResult.ViewData.Model = image;
                  return partialViewResult;
              }
              else
              {
                  // DO NOTHING, HOW?
              }
          }
  
          return RedirectToAction("Error", "Home");
      }
  </code></pre>