OnBackKeyPress未按预期工作(OnBackKeyPress is not working as expected)

 在我的应用程序中，我有这两个功能。 自从我添加了OnBackKeyPress函数后， OnBackKeyPress的if语句即使我按下后退按钮也是如此（可能是因为e.cancel= true;在OnBackKeyPress ）。 
 
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
   // On back navigation there is no need to save state.
   if (e.NavigationMode != System.Windows.Navigation.NavigationMode.Back)
   {
      StoreState(); //this should not run when i press back button
   }

   FilterPreviewPivot.SelectionChanged -= FilterPreviewPivot_SelectionChanged;
   base.OnNavigatedFrom(e);
}

protected override void OnBackKeyPress(CancelEventArgs e)
{
   while (NavigationService.CanGoBack) NavigationService.RemoveBackEntry();
   NavigationService.Navigate(new Uri("/Chooser.xaml", UriKind.Relative));

   // cancel the navigation
   e.Cancel = true;
}

In my app I have these two functions. Ever since I added the OnBackKeyPress function, the if statement inside OnNavigatedFrom is true even if I press back button (may be because e.cancel= true; inside OnBackKeyPress).
 
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
   // On back navigation there is no need to save state.
   if (e.NavigationMode != System.Windows.Navigation.NavigationMode.Back)
   {
      StoreState(); //this should not run when i press back button
   }

   FilterPreviewPivot.SelectionChanged -= FilterPreviewPivot_SelectionChanged;
   base.OnNavigatedFrom(e);
}

protected override void OnBackKeyPress(CancelEventArgs e)
{
   while (NavigationService.CanGoBack) NavigationService.RemoveBackEntry();
   NavigationService.Navigate(new Uri("/Chooser.xaml", UriKind.Relative));

   // cancel the navigation
   e.Cancel = true;
}

原文：https://stackoverflow.com/questions/21529128