Please try this, I can't use VS.Net now, just some hint.
1. Add a web browser control.
2. On the event "OnBeforeNavigate", check the url will naviage to. If the uri is the special uri you set in the html file, the canel it and call some functions.
Soem thing like this:
protected void OnBeforeNavigate(object sender, BeforeNavigateEventArgs e)
{
MessageBox.Show("User tried to go to: " + e.Url);
e.Cancel = true; // Prevents the control to load the new page
}