private async void clickSearchButton(object sender, RoutedEventArgs e) { var messageDialog = new MessageDialog(""); messageDialog.Commands.Add(new UICommand("Close")); messageDialog.DefaultCommandIndex = 0; messageDialog.CancelCommandIndex = 1; if (searchMessage.Text == "") { messageDialog.Content = "Please input the message for search"; } else { StringBuilder result = TodoItemDataBase.query(searchMessage.Text); messageDialog.Content = result.ToString(); } await messageDialog.ShowAsync(); }