Open
Description
Description
App.Current.PageDisappearing is not raised when a page is popped from the navigation stack.
Steps to Reproduce
- Create a File->New MAUI app.
- Replace the constructor in App.xaml.cs with this:
public partial class App : Application
{
public App()
{
InitializeComponent();
//MainPage = new AppShell();
MainPage = new NavigationPage(new MainPage());
App.Current.PageAppearing += Current_PageAppearing;
App.Current.PageDisappearing += Current_PageDisappearing;
}
private void Current_PageDisappearing(object sender, Page e)
{
Debug.WriteLine($"Current_PageDisappearing {e}");
}
private void Current_PageAppearing(object sender, Page e)
{
Debug.WriteLine($"Current_PageAppearing {e}");
}
}- Replace the click-handler in MainPage.xaml.cs with this:
private void OnCounterClicked(object sender, EventArgs e)
{
App.Current.MainPage.Navigation.PushAsync(new ContentPage { Title="Child Page"});
}- Run the app.
- Look at the debug output from the new
Current_PageDisappearingandCurrent_PageAppearingevent handlers. - Observe that MainPage and NavigationPage are reported as appearing.
[0:] Current_PageAppearing MauiPopNavigationBug.MainPage
[0:] Current_PageAppearing Microsoft.Maui.Controls.NavigationPage
- Tap the button.
- Observe
MainPagedisappears andContentPageappears.
[0:] Current_PageDisappearing MauiPopNavigationBug.MainPage
[0:] Current_PageAppearing Microsoft.Maui.Controls.ContentPage
- Tap the back button
- [BUG] Observe the ContentPage is popped, the MainPage appearing event is raised but the ContentPage PageDisappearing event is not raised.
[0:] Current_PageAppearing MauiPopNavigationBug.MainPage
Link to public reproduction project repository
https://github.com/Keflon/MauiPopNavigationBug
Version with bug
7.0 (current)
Last version that worked well
Unknown/Other
Affected platforms
iOS, Android, Windows, I was not able test on other platforms
Affected platform versions
All current / latest.
Did you find any workaround?
Subscribe to the following events:
App.Current.DescendantAdded += CurrentApplication_DescendantAdded;
App.Current.DescendantRemoved += CurrentApplication_DescendantRemoved;Do something like this:
private void CurrentApplication_DescendantAdded(object sender, ElementEventArgs e)
{
if (e.Element is Page cp)
{
cp.Disappearing += PageDisappearing;
cp.Appearing += PageAppearing;
}
}
private async void CurrentApplication_DescendantRemoved(object sender, ElementEventArgs e)
{
if (e.Element is Page cp)
{
cp.Appearing -= PageAppearing;
await Task.Yield(); // Reason: The disappearing event was/is raised after the DescendantRemoved event.
cp.Disappearing -= PageDisappearing;
}
}The PageAppearing and PageDisappearing events are correctly raised.
The above is not tested, however it is a subset of working CurrentApplication_DescendantAdded and CurrentApplication_DescendantRemoved implementations found here: https://github.com/Keflon/Maui.MvvmZero/blob/eada8a7059fadc248de13456b3be627373384bd8/Maui.MvvmZero/Implementation/PageServiceZero.cs
Relevant log output
[0:] Current_PageAppearing MauiPopNavigationBug.*
[0:] Current_PageDisappearing MauiPopNavigationBug.*