如何在应用程序关闭或 WinUI3 应用程序中输入背景时保存数据

Question

How to intercept app_closing or app_entering_background in WinUi 3 app.

In UWP apps we do have Application_EnteredBackground event, in which we can intercept app close, we use GetDeferral() to save data.

Is there any same kind of event in WinUI 3 apps, I need to save data on app close, or entering background.

Tried window_VisibilityChanged and window_Closed events, but not able to use GetDeferral() .

Kindly help

Thanks in advance.

Noorul

Answer 1

Here is my test code for your reference, you can intercept the closing event.

(closing is executed before closed)

public sealed partial class MainWindow : Window
{
    private AppWindow _appWindow;

    public MainWindow()
    {
        this.InitializeComponent();
        
        this.Closed += OnClosed;

       _appWindow = GetAppWindowForCurrentWindow();
       _appWindow.Closing += OnClosing;
    }
   
    private void OnClosed(object sender, WindowEventArgs e)
    {
        string btnText = myButton.Content.ToString();
    }

    private void OnClosing(object sender, AppWindowClosingEventArgs e)
    {
        string btnText = myButton.Content.ToString();

    }
    private AppWindow GetAppWindowForCurrentWindow()
    {
        IntPtr hWnd = WindowNative.GetWindowHandle(this);
        WindowId myWndId = Win32Interop.GetWindowIdFromWindow(hWnd);
        return AppWindow.GetFromWindowId(myWndId);
    }

    private void myButton_Click(object sender, RoutedEventArgs e)
    {
        myButton.Content = "Clicked";
    }
}