Migrating Windows 8 UWP applications to Windows 10: replacing MessageDialogs with new ContentDialogs

When Windows 8 came out, UWP applications were somewhat limited, and if you wanted to show a simple message to the user, you probably used the MessageDialog class. In Windows 10, things have improved, and there's a new feature called ContentDialog.

The ContentDialog allows better content customization, letting you even specify custom XAML code for the dialog box.

Hope this helps!