Winui3 OnClosin in the single page

Question

My app has multiple pages. When I press the Close key in the toolbar, how can I detect the OnClosing event in the single page to avoid closing the app instead of going back to the MainWindow with "this.Frame.GoBack();" ?

I can only catch OnClosing on MainWindow

Answer 1

You can use the Unloaded event on Pages.

*.xaml

<local:TestPage Unloaded="TestPage_Unloaded" />

*.xaml.cs

private void TestPage_Unloaded(object sender, RoutedEventArgs e)
{
    // Do your page closing work here...
}

Answer 2

You could store a reference to the window in a property or field in your App.xaml.cs class as suggested here and then handle the Closing event of the window in the Page class something like this:

public sealed partial class MainPage : Page
{
    private Window _parentWindow;

    public MainPage()
    {
        this.InitializeComponent();
        this.Loaded += OnLoaded;
        this.Unloaded += OnUnloaded;
    }

    private void OnLoaded(object sender, RoutedEventArgs e)
    {
        _parentWindow = (Application.Current as App)?.m_window;
        if (_parentWindow != null)
            _parentWindow.Closed += OnWindowClosed;
    }

    private void OnUnloaded(object sender, RoutedEventArgs e)
    {
        if (_parentWindow != null)
            _parentWindow.Closed -= OnWindowClosed;
    }

    private void OnWindowClosed(object sender, WindowEventArgs args)
    {
        // Prevent the window from being closed based on some logic of yours...
        args.Handled = true;
    }
}