Updating the current window on demand

[dodge55]

I have a WPF control TBStatus that is a TextBlock, with a hidden 'Please Wait...'.

What's the best way to actually update the screen after each delay? It waits the 10 seconds and puts up the control. I tried a Dispatcher and same thing. What's the trick?

TBStatus.Foreground = Brushes.Red;

for (i = 0; i < 5; i++)
{
TBStatus.Visibility = Visibility.Visible;
Thread.Sleep(1000);
TBStatus.Visibility = Visibility.Hidden;
Thread.Sleep(1000);
}
TBStatus.Visibility = Visibility.Visible;