Question

In a WPF UserControl, I have to make to call to a WebService. I am making this call on a separate thread but I want to inform the user that the call may take some time.

The WebMethod returns me a collection of objects and I bind it to a ListBox in my UC. So far, so good… This part works really well. However, I want to display a progress bar (or an animation of any kind…) during the call. This animation would be on top and centered in the ListBox control.

I tried Adorner and it partially works. However, I have to draw all controls in protected override void OnRender(DrawingContext drawingContext)… I simply want to add a control for a couple of seconds…

Anybody has an idea of how I could achieve this?

Thanks!

Answer 1

Don’t go with the adorner – what I do is have two separate container controls (usually grids) that occupy the same area of the screen. One is my ‘progress’ control, and the other is my ‘content’ control. I set the visibility of the progress control to Collapsed and the visibility of the content control to Visible by default.

If you have it set up that way, when you start the asynchronous call to the webservice you can make the progress control visible and the content control collapsed. When the webservice finishes, have it use Dispatcher.BeginInvoke to update the UI, and at that point, switch the progress control back to collapsed and the content control back to visible.

I generally make the progress control indeterminate. Here is an example; in this, I have a separate UserControl called ProgressGrid that has my progress bar.

    <Grid x:Name='layoutRoot'>         <Grid x:Name='contentGrid' HorizontalAlignment='Center' VerticalAlignment='Center' Visibility='Visible'>              <!-- snip -->         </Grid>          <controls:ProgressGrid x:Name='progressGrid' Text='Signing in, please wait...' Visibility='Collapsed'/>     </Grid> 

And in the code behind, just something simple like this:

    private void SignInCommand_Executed(object sender, ExecutedRoutedEventArgs e)     {         contentGrid.Visibility = Visibility.Collapsed;         progressGrid.Visibility = Visibility.Visible;     }