Always got exception when using webBrowser progress changed
<p>Do you know why I always got this exception?
<img src="http://i.stack.imgur.com/LdmCv.png" alt="exception"></p>

<p>this is my code </p>

<pre><code>private void webBrowser1_ProgressChanged(object sender, WebBrowserProgressChangedEventArgs e)
    {
        toolStripProgressBar1.Maximum = (int)e.MaximumProgress;
        toolStripProgressBar1.Value = (int)e.CurrentProgress;
    }
</code></pre>

<p>I would appreciate any answer, thank you.</p>
