title: Detect when a click downloads a file in winforms WebBrowser component
body: <p>I have a simple webpage with only 3 links displayed in my webbrowser component:</p>
  
  <pre><code>&lt;a href="/newpage1.html" id="el-1"&gt;Go to new page 1&lt;/a&gt;
  &lt;a href="/newpage2.html" id="el-2"&gt;Go to new page 2&lt;/a&gt;
  &lt;a href="/file.zip" id="el-1"&gt;Download file&lt;/a&gt;
  </code></pre>
  
  <p>I register an event handler for the click event on a list of elements</p>
  
  <pre><code>foreach (HtmlElement e in this.webBrowserMain.Document.GetElementsByTagName("a")){
      e.Click += this.SingleElementClickHandler;
  }
  </code></pre>
  
  <p>Let's assume that server side the following headers are sent for the file /file.zip</p>
  
  <pre><code>header('Content-type: application/zip');
  header('Content-Disposition: attachment; filename="file.zip"');
  </code></pre>
  
  <p>How can I write the SingleElementClickHandler to pop up a message box with the text "Hello" when a file is downloaded and <strong>not</strong> when another web page is opened?</p>
  
  <p>I can't use any third party component.</p>