private async void btnTopic_Click(object sender, RoutedEventArgs e)
 {
     TopicFlyout.ShowAt(sender as Button);
     if (topicVM.Items == null || topicVM.Items.Count == 0)
     {
         await topicVM.GetTopic();
     }
 }
 private void TextTopic_QuerySubmitted(AutoSuggestBox sender, AutoSuggestBoxQuerySubmittedEventArgs args)
 {
     txtContent.Text += args.QueryText;
     TopicFlyout.Hide();
 }
 private void listTopic_ItemClick(object sender, ItemClickEventArgs e)
 {
     txtContent.Text += (e.ClickedItem as RcmdTopicModel).display;
     TopicFlyout.Hide();
 }