title: Can a URL change on postback?
body: <p>I only need to parse URL Request.Querystrings on GET, not on postback, right?</p>
  
  <pre><code>if(!IsPostBack)
  {
      Viewstate["magic_number"] = Parse(Request.Query);
  }
  </code></pre>
  
  <p>The user can't be expected to modify the URL in the Request for subsequent postbacks, or can they?</p>
  
  <p>Motivation for question-- I don't control the javascript snippet that does the postback, so it's something of blackbox to me.</p>