Add background while uploading data wp7?

anyone know how to add ba开发者_开发技巧ckground while uploading data ?, currently performanceprogressbar just shown while uploading data. i try to use rectangle to cover screen but its doesn't look really nice. current codes:

    ProgressBar bar = new ProgressBar();
    Rectangle loadi![enter image description here][1]ng = new Rectangle() 
        { 
             Height = 800, 
             Width = 480, 
             Fill =  new SolidColorBrush(Colors.Black), Opacity = 0.2 
        };  

     bar.IsIndeterminate = true;
     this.LayoutRoot.Children.Add(loading);
     this.LayoutRoot.Children.Add(bar); 

something like this,

any suggestion ?, thanks.

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Have you considered using a Popup control? You can add other controls to it and display it whenever the loading progress changes (e.g. starts loading something).

Here is a demo you might be interested in for the situation.