title: Unable to send POST data of a form
body: <p>i have a problem with a Web Post Form.
  I have download the page, I extrapolated the two required values (<em>form_build_id</em> and <em>form_token</em>), but once sent the POST the server does not receive anything in POST.</p>
  
  <p>Excluded errors:</p>
  
  <ul>
  <li>Wrong link (can download the page).</li>
  <li>Incorrect extrapolated data (verified).</li>
  <li>Wrong string myParameters (verified).</li>
  <li>I have tested the Form manually and it work fine.</li>
  </ul>
  
  <p>Some idea? There I slam my head for two days!</p>
  
  <pre><code>using (WebClientEx wc = new WebClientEx())
          {
              wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
              string HTMLPage = wc.DownloadString(CREAT_TICKET_URL);
  
              string form_build_id    = SearchValue(HTMLPage, "&lt;input type=\"hidden\" name=\"form_build_id\"", "value=\"", "\"  /&gt;");
              string form_token       = SearchValue(HTMLPage, "&lt;input type=\"hidden\" name=\"form_token\"", "value=\"", "\"  /&gt;");
  
              string myParameters = "macchina=" + cmacExtID + "&amp;utente=" + custExtID + "&amp;oggetto=" + Title + "&amp;body=" + Note + "&amp;op=Conferma&amp;form_build_id=" + form_build_id + "&amp;form_token=" + form_token + "&amp;form_id=app_form_new_ticket";
  
              string HtmlResult = wc.UploadString(CREAT_TICKET_URL, myParameters);
          }
  </code></pre>
  
  <blockquote>
    <p>Note: WebClientEx class inherits WebClient. I used this approach to other forms such as login and work.</p>
  </blockquote>
  
  <p>The final question is: if this approach is wrong, what is the best way to do this sequence of operations "download the page, extract the values from the HTML, send post form"?</p>