private async void UIElement_OnTapped(object sender, TappedRoutedEventArgs e) { if (LightButton.IsChecked == true) { ApplicationData.Current.LocalSettings.Values["AppTheme"] = (int)ElementTheme.Light; } else { ApplicationData.Current.LocalSettings.Values["AppTheme"] = (int)ElementTheme.Dark; } MessageDialog msgDialog = new MessageDialog("Changing the theme requires restarting the application, would you like to restart now?"); UICommand cancelCommand = new UICommand("Cancel"); UICommand restartCommand = new UICommand("Restart"); msgDialog.Commands.Add(restartCommand); msgDialog.Commands.Add(cancelCommand); IUICommand command = await msgDialog.ShowAsync(); if (command.Equals(restartCommand)) { AppRestartFailureReason result = await CoreApplication.RequestRestartAsync(""); } }