title: URL with multiple parameters as a query string in ASP.NET
body: <p>In ASP.NET, I build a string <code>redirectURL</code> to redirect to <code>ADFS</code> form with multiple query string parameters. One such complex parameter is the <code>returnURL</code> with multiple parameters. </p>
  
  <p>My problem is that only the first parameter of the <code>returnURL</code> is available when it actually return. </p>
  
  <pre><code>E.g. redirectURL = &lt;br&gt; 
  https://aaa.aaa/adfs/Form.aspx &lt;br&gt;
  ?DomainName=domain &lt;br&gt;
  &amp;AccountName=account &lt;br&gt;
  &amp;returnURL=https://bbb.bbb/MyPage.aspx?param1=111&amp;param2=222
  </code></pre>
  
  <p>I know it complicates when identify the <code>&amp;amp symbol</code> of actual parameters and parameters in <code>returnURL</code>. Please help me to fix this. </p>
  
  <p>Thanks in advance.  </p>