title: get main part of url including virtual directory
body: <p>I am working with .net 4.0 c#.</p>
  
  <p>I want to be able to get the url from the current http request, including any virtual directory. So for example (request and sought value):</p>
  
  <p><a href="http://www.website.com/shop/test.aspx" rel="noreferrer">http://www.website.com/shop/test.aspx</a> -> <a href="http://www.website.com/shop/" rel="noreferrer">http://www.website.com/shop/</a></p>
  
  <p><a href="http://www.website.com/test.aspx" rel="noreferrer">http://www.website.com/test.aspx</a> -> <a href="http://www.website.com/" rel="noreferrer">http://www.website.com/</a></p>
  
  <p><a href="http://website.com/test.aspx" rel="noreferrer">http://website.com/test.aspx</a> -> <a href="http://website.com/" rel="noreferrer">http://website.com/</a></p>
  
  <p>How is it possible to achieve this?</p>