title: Propagating QueryString parameter in RedirectToAction calls
body: <p>I want to make sure that a particular parameter in the QueryString, in my case the <code>request_id</code> is propagated to the redirected action. </p>
  
  <p>Say for example, I have an Action <code>First</code>,</p>
  
  <pre><code>[HttpPost]
  public ActionResult First() 
  {
      ////////////////////
      // Lots of code ...
      ////////////////////
  
      return RedirectToAction("Second");
  }
  </code></pre>
  
  <p>Now say, the <code>First</code> postback had a parameter in the <code>QueryString</code>, which I would like to pass to the <code>Second</code> action. One way to do it would be to pass the value in the <code>RedirectToAction</code> call itself,</p>
  
  <pre><code>string requestId = Request.QueryString[REQUEST_ID_KEY];
  return RedirectToAction("Second", new { REQUEST_ID_KEY = requestId });
  </code></pre>
  
  <p>But I have to do this in a series of Actions and I am unwilling to incorporate request id propagation logic inside the action. It would be better if I could incorporate this inside an <code>ActionFilter</code>, but I cant figure out how to add parameters to the QueryString from an ActionFilter. Any ideas?</p>