Programming with .NET - General

Re: KeyDown event throws an exception when MessageBox.Show(e.Key.ToString()) is called

Jonathan Shen – MSFT — Thu, 11 Jun 2009 10:46:12 GMT

Hi Grey Matter,

This is a known issue and has been fixed in Silverlight 3. Currently, the workaround is to do it like this.

        private void myTextBox_KeyDown(object sender, KeyEventArgs e)
        {
            Dispatcher.BeginInvoke(()=>{
                MessageBox.Show(e.Key.ToString());
            });
        }

Best regards,

Jonathan

Re: KeyDown event throws an exception when MessageBox.Show(e.Key.ToString()) is called

Grey Matter — Sun, 07 Jun 2009 23:31:28 GMT

Thank for your explanation, but I still have some doubts:

If any other thread (event) tries to display MessageBox at the same time why can't I catch it at my breakpoint?

It's caught only once and sometimes drops on it. By the way, my Firefox drops too.

Then I added a TextBlock to check a chance of multiple KeyDown events and was putting every got key to the TextBlock's content.

But no multiple events occurred.

Re: KeyDown event throws an exception when MessageBox.Show(e.Key.ToString()) is called

varshavmane — Sun, 07 Jun 2009 12:30:34 GMT

Check this link:

http://blogs.vertigo.com/personal/keithc/Blog/archive/2008/12/02/keydown-and-messagebox-dont-mix-well-in-silverlight.aspx

Its will answer your post. Hope it helps you

KeyDown event throws an exception when MessageBox.Show(e.Key.ToString()) is called

Grey Matter — Sat, 06 Jun 2009 22:43:35 GMT

The TextBox's event:

private void TextBox_KeyDown(object sender, KeyEventArgs e)
{
    MessageBox.Show(e.Key.ToString());
}

throws an exception on any key pressed just except the first one.

It doesn't happen at all on the KeyUp event with the same code within.

What does it mean?