How to show a full screen Modal ContentDialog in Windows Phone 8.1

Question

When a user is trying to login to my app, I am displaying a ContentDialog containing a few TextBlocks and a ProgressBar.

I choose ContentDialog because it is modal a

Answer 1

You can for example put a Grid as a content of your ContentDialog and set its Height/Width as Bounds of Current Window or your LayoutGrid:

// your code
stk.VerticalAlignment = Windows.UI.Xaml.VerticalAlignment.Center;
Grid contentGrid = new Grid();
contentGrid.Height = Window.Current.Bounds.Height;
contentGrid.Width = Window.Current.Bounds.Width;
// or from LayoutGrid
//contentGrid.Height = LayoutRoot.ActualHeight;
//contentGrid.Width = LayoutRoot.ActualWidth;
contentGrid.Width -= 40; // it seems that ContentDialog has some defaul margin
contentGrid.Children.Add(stk);

ContentDialog dlg = new ContentDialog();
dlg.Content = contentGrid;
SolidColorBrush color = new SolidColorBrush(Colors.Black);
color.Opacity = 0.7;
dlg.Background = color;
await dlg.ShowAsync();

You can also think of using a PopUp.