Canceling Navigation

The OnNavigatingFrom method offers the opportunity to cancel navigation using the NavigatingCancelEventArgs parameter.

NavigatingCancelEventArgs has the following properties:

NavigationMode—An enum value that indicates the type of navigation. This value may be Back, Forward, New, or Refresh.

Uri—The destination URI.

Cancel—Setting this value to true cancels the navigation.

The NavigationCancelEventArgs class subclasses CancelEventArgs, which provides the Cancel property. By setting this property to true, the page can prevent the navigation from occurring, as shown in the following excerpt:

Click here to view code image

protected override void OnNavigatingFrom(
    System.Windows.Navigation.NavigatingCancelEventArgs e)
{
    base.OnNavigatingFrom(e);
    MessageBoxResult boxResult = MessageBox.Show(
        "Leave this page?", "Question", MessageBoxButton.OKCancel);
    if (boxResult != MessageBoxResult.OK)
    {
        e.Cancel = true;
    }
}