How to remove shadow of ContentDialog in UWP?

How to remove shadow of ContentDialog in UWP?

Please check Z-depth and shadow document.

ThemeShadow automatically casts shadows when applied to any XAML element in a Popup. It will cast shadows on the app background content behind it and any other open Popups below it.

If you want to disable it, the better way is that set Container a new Translation in loaded event, and make z value as low enough.

For example: (place the style of ContentDialog in the page resource and give it new name MyContentDialog ).

var diaog = new ContentDialog() { Title = "hello world!",Style= (Style)Resources["MyContentDialog"] ,SecondaryButtonText="ok"};    
await diaog.ShowAsync();  

Set the new Translation.

private void Container_Loaded(object sender, RoutedEventArgs e)  
{  
  var border = sender as Border;  
  border.Translation = new Vector3(0, 0, -100);  
}