Border on Content Dialog UWP

Question

Hello,
I want put a border in ContentDialog, but is Incorrect.
I'd like as the CornerRadius.

Answer 1

You can derive a control from ContentDialog and copy the default style (in <ContentDialog.Resources>) from generic.xaml (inside <Style TargetType="ContentDialog">)
Then you can change <Border x:Name="BackgrounElement" (Background, bug in this editor...)
for example with :

              BorderThickness="5"  
              BorderBrush="Red"                                          
              CornerRadius="15"  

I get :