How to use the WPF progressbar ?

Question

Hello

I am trying to use the WPF progressbar control with the IsIndeterminate property set to true. The problem I have, is that it doesn't get updated.

I am doing something like this:

pbProgressBar.Visibility = Visibility.Visible; 
//do time consuming stuff
pbProgressBar.Visibility = Visibility.Hidden;

I tried to wrap this in a thread and then dispatch it with the Dispatcher object. How should I solve this problem :).

Answer 1

You must do the time consuming stuff on a background thread, and you must ensure that the Visibility isn't set back to Hidden until after the background thread has done its thing. The basic process is as follows:

private void _button_Click(object sender, RoutedEventArgs e)
{
   _progressBar.Visibility = Visibility.Visible;

   new Thread((ThreadStart) delegate
   {
       //do time-consuming work here

       //then dispatch back to the UI thread to update the progress bar
       Dispatcher.Invoke((ThreadStart) delegate
       {
           _progressBar.Visibility = Visibility.Hidden;
       });

   }).Start();
}

HTH, Kent