如何在wp8中滚动到列表框的SelectedIndex

Question

I am having problem scrolling to selected index of listbox in 1st page load event. When the page loads for the 1st time it cannot scroll to the selected index while the selected index is changed and highlighted. When I navigate to another page and come back to this page then it scroll to the selected index. I didn't understand why it could not scroll at 1st page load.

void MainPage_Loaded(object sender, RoutedEventArgs e)
{
    try
    {
      ApplicationBarIconButton btn = (ApplicationBarIconButton)ApplicationBar.Buttons[1];
      if (PlayState.Playing == BackgroundAudioPlayer.Instance.PlayerState)
      {
         btn.IconUri = new Uri("/Images/pause.png", UriKind.Relative);
         BackgroundAudioPlayer player = BackgroundAudioPlayer.Instance;
         if (player.Track != null)
         {
            currentChapter = ds.getChapter(Convert.ToByte(player.Track.Artist.Split(DataSource.TRACKARTISTDELIMTER)[0])); 
            lsbReadingChapter.ItemsSource = ds.getArabicTextWithTranslation(currentChapter);

           //Get Position and Start timer
           fillRecitation();
           double position = player.Position.TotalSeconds;
           setSelectedIndex(position);
           recitationTimer.Start();
         }
      }
      else
      {
         lsbReadingChapter.ItemsSource = ds.getArabicTextWithTranslation(currentChapter);
         recitationTimer.Stop();
         btn.IconUri = new Uri("/Images/play.png", UriKind.Relative);
         scrollIntoSelectedItem(Convert.ToByte(App.Recent.AyaID));

       }

       txtTitle.Text = HCI.convertToArabicIndicString(currentChapter.ChapterID) + " - " + currentChapter.SuraName + " - " + HCI.convertToArabicIndicString(currentChapter.Ayas);

       if (currentChapter != null)
       {
         if (ds.chapterAvailable(currentChapter))
            txtAvailable.Text = "available";
         else
            txtAvailable.Text = string.Empty;
       }

       if (lsbReadingChapter.SelectedIndex != -1)
         scrollIntoSelectedItem(lsbReadingChapter.SelectedIndex); //scroll to index
  }
  catch (Exception) { }
}

void scrollIntoSelectedItem(int index)
{
   lsbReadingChapter.SelectedIndex = lsbReadingChapter.Items.Count - 1;
   lsbReadingChapter.UpdateLayout();
   lsbReadingChapter.ScrollIntoView(lsbReadingChapter.SelectedIndex);

   lsbReadingChapter.SelectedIndex = index;
   lsbReadingChapter.UpdateLayout();
   lsbReadingChapter.ScrollIntoView(lsbReadingChapter.SelectedIndex);

}

This doesn't work only in 1st page load event. I didn't understand what causes it not scroll?

Thanks!

Answer 1

在页面加载中使用它。

this.Page.MaintainScrollPositionOnPostBack = true;