title: How to export a List<t> to Excel as the result of a web request
body: <p>I want to know how to export a List (like a datagrid) to excel.</p>
  
  <p>I am not talking about a CSV, but a real xlsx file that is XML and compressed, etc.</p>
  
  <p>I have only seen a few examples about Open XML from Microsoft.</p>
  
  <p>Second thing and the most important, how do you save that excel not on disk at all, but instead write it back to the client on the web using response.write....  </p>
  
  <p>Bill.</p>