I have a WebBrowser control which is being instantiated dynamically from a background STA thread because the parent thread is a BackgroundWorker and has lots of other things to do.

The problem is that the Navigated event never fires, unless I pop a MessageBox.Show() in the method that told it to .Navigate(). I shall explain:

ThreadStart ts = new ThreadStart(GetLandingPageContent_ChildThread);
Thread t = new Thread(ts);
t.SetApartmentState(ApartmentState.STA);
t.Name = "Mailbox Processor";
t.Start();

protected void GetLandingPageContent_ChildThread()
{
 WebBrowser wb = new WebBrowser();
 wb.Navigated += new WebBrowserNavigatedEventHandler(wb_Navigated);
 wb.Navigate(_url);
 MessageBox.Show("W00t");
}

protected void wb_Navigated(object sender, WebBrowserNavigatedEventArgs e)
{
 WebBrowser wb = (WebBrowser)sender; // Breakpoint
 HtmlDocument hDoc = wb.Document;
}

This works fine; but the messagebox will get in the way since this is an automation app. When I remove the MessageBox.Show(), the WebBrowser.Navigated event never fires. I've tried supplanting this line with a Thread.Sleep(), and by suspending the parent thread.

Once I get this out of the way, I intend to Suspend the parent thread while the WebBrowser is doing its job and find some way of passing the resulting HTML back to the parent thread so it can continue with further logic.

Why does it do this? How can I fix it?

If someone can provide me with a way to fetch the content of a web page, fill out some data, and return the content of the page on the other side of the submit button, all against a webserver that doesn't support POST verbs nor passing data via QueryString, I'll also accept that answer as this whole exercise will have been unneccessary.