mahapp messagedialog usage
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this.MetroDialogOptions.ColorScheme = MetroDialogColorScheme.Accented;
var msgbox_settings = new MetroDialogSettings { AffirmativeButtonText = metromsgbox_yes, NegativeButtonText = metromsgbox_no };
var msgbox_result = await this.ShowMessageAsync(
msgbox_logout_title, msgbox_logout_message, MessageDialogStyle.AffirmativeAndNegative, msgbox_settings);
_shutdown = msgbox_result == MessageDialogResult.Affirmative;
if (_shutdown)
{
if (NotifyIcon != null) NotifyIcon.Dispose();
Application.Current.Shutdown();
}
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Source : https://github.com/MahApps/MahApps.Metro/issues/1523