private async void messengerCallback(PopupMessage obj) { if (obj.AceptMessageCallBack != null) { var result = await this.ShowMessageAsync("Save Data", obj.Notification, MessageDialogStyle.AffirmativeAndNegative); if (result == MessageDialogResult.Affirmative) { obj.AceptMessageCallBack(); } } else { await this.ShowMessageAsync("Save Data", obj.Notification, MessageDialogStyle.Affirmative); } }