title: C# web post request with a dynamic string inside
body: <p>I've been trying for many days to do that post request, but actually it doesn't work, so let me explain: I've to login onto a website using <code>HttpWebRequest</code> (the website is an HTTPS, but it doesn't matter) so I picked the post string from the post request, but it has an alphanumeric random generated string inside, which changes on every login request and I don't understand how can I get it. That's an example of the post string: </p>
  
  <blockquote>
    <p><strong>tp=f8279b6fedd63d2f6f6b483c4c6bf42c&amp;cir=7630440</strong>&amp;username=[username
    here]&amp;password=[password
    here]&amp;reopen_account=on&amp;remember_me=on&amp;tz=120%21120&amp;nid=&amp;action=login</p>
  </blockquote>
  
  <p>The bold string changes on every login and that's my problem: how can I login on this site with a web request?. Thank you and sorry for my, maybe, bad english.</p>