How to handle back button for only on a certain page?

Question

In short, I would like to handle the back button only on certain page to go back to previous page, but ignore (let default operation/ close the app) on the rest of the pages.

So for my example, I would like to handle back button only for CurrentPage. So, I put this code on my CurrentPage.xaml.cs

public CurrentPage()
{
   this.InitializeComponent();
   SystemNavigationManager.GetForCurrentView().BackRequested += App_BackRequested;
}

private void App_BackRequested(object sender, BackRequestedEventArgs e)
{
   this.Frame.Navigate(typeof(PreviousPage), e);
   e.Handled = true;
}

But, when I got into PreviousPage, pressing Back Button will go to PreviousPage again. I cannot quit the app.

If I add this on the PreviousPage.xaml.cs, then pressing BackButton from CurrentPage will result to go back to PreviousPage and close the app automatically.

public PreviousPage()
{
   this.InitializeComponent();
   SystemNavigationManager.GetForCurrentView().BackRequested += App_BackRequested;
}

private void App_BackRequested(object sender, BackRequestedEventArgs e)
{
   Application.Current.Exit();
   e.Handled = true;
}

Do you have any idea how to handle back button on single page?

Answer 1

When you leave the CurrentPage, you should also remove the back pressed event handler SystemNavigationManager.GetForCurrentView().BackRequested -= App_BackRequested; . Without this the code gets called even if you've left the page already.