title: WebClient.DownloadFile 404 errors with HTML characters in URI?
body: <p>I'm using the WebClient class to download files from a web site and have a couple of questions.</p>
  
  <ol>
  <li><p>When the URIs have HTML characters in the URI path (eg <a href="http://foo.com/path1" rel="nofollow noreferrer">http://foo.com/path1</a><code>&amp;amp;</code>path2.pdf) I get 404 (not found) errors.  How can I prevent this?  I thought HTML characters were safe?</p></li>
  <li><p>When the URIs represent a directory (eg <a href="http://foo.com/path" rel="nofollow noreferrer">http://foo.com/path</a>) I get 403 (forbidden) errors.  I understand why this is occuring but how can I test my URI to see if it represents a directory with no index page.</p></li>
  </ol>