title: Pass Query string to mvc view action
body: <p>I want to return to same page with error message along with <code>query string</code> when the model is invalid in post operation</p>
  
  <p>My code is here</p>
  
  <pre><code>public ActionResult Action1(string Key)
  {
  
      // do something
  }
  
  [HttpPost]
  public ActionResult Action1(Model user)
  {
      if (ModelState.IsValid)
                  {
      // do some stuff here
      }
      else
       // redirect to same page with query string key and also error message
  }
  </code></pre>
  
  <p>Please suggest the line I need to add when the model is invalid to stay in the same page by showing the error message.</p>