更改可见性不适用于C＃windows phone 8

Question

I'm trying to display a progessbar during some work but the visibility doesn't change...

private void GestureListener_PinchCompleted(object sender, PinchGestureEventArgs e)
{
    progressBar.Visibility = System.Windows.Visibility.Visible;
    DoWork();//quite long (4-5 seconds)
    progressBar.Visibility = System.Windows.Visibility.Collapsed;
}

Is there a resfreh method or something like that? Am I doing something wrong?

Answer 1

You are executing DoWork() in the UI thread, blocking it for 4 to 5 seconds. This is why you are unable to see the progress bar.

Consider to call DoWork in a separate thread:

private async void GestureListener_PinchCompleted(object sender, PinchGestureEventArgs e)
{
    progressBar.Visibility = System.Windows.Visibility.Visible;
    await Task.Run(()=> DoWork()); //quite long (4-5 seconds)
    progressBar.Visibility = System.Windows.Visibility.Collapsed;
}

Asynchronous Programming For Windows Phone 8