WCF异步方法仅在调试时有效

Question

I have a weird issue, I'm building a Universal App and everything works when I'm debugging but when I run without debugging the emulator tries to open the application and then crashes.

Here is the code I know is failing:

private void MenuPage_Loaded(object sender, RoutedEventArgs e)
{
   SetItemSource();
}

private async void SetItemSource()
{
   MenuItems =  await AppWinService.GetMenuEntriesAsync();     
   ItemSource = new ObservableCollection<AlphaKeyGroup<Menu>>
         ((AlphaKeyGroup<Menu>.CreateGroups(MenuItems,
                                            CultureInfo.CurrentUICulture, 
                                            s => s.MenuName, 
                                            true)));

   ((CollectionViewSource)Resources["MenuGroups"]).Source = ItemSource;

 }

Any suggestions? Thanks in advance.

Answer 1

Are you sure MenuItems is coming back valid for all situations ? What happens on timeout?

Why not check for null just to be safe:

MenuItems =  await AppWinService.GetMenuEntriesAsync();   

if ((MenuItems != null) && (MenuItems.Any())
{
   ItemSource = new ObservableCollection<AlphaKeyGroup<Menu>>(
                                          (AlphaKeyGroup<Menu>.CreateGroups(MenuItems,
                                           CultureInfo.CurrentUICulture, 
                                           s => s.MenuName, 
                                           true)));

  ((CollectionViewSource)Resources["MenuGroups"]).Source = ItemSource;
}
else 
{ 
   MessageBox.Show("Failure to get data"); 
}