c# - 应用程序暂停时不会调用 OnNavigatedFrom

Question

今天我遇到了一个奇怪的问题 - 似乎在我的设备上 (v. 8.10.14203.306) OnNavigatedFrom 事件在应用程序暂停时没有被调用。据我记得不久前它工作正常，而且非常好 as documentation stays :

Note On Windows Phone, OnNavigatedFrom() is called when the app is suspended. OnNavigatedTo() is not called when the app is resumed.

我试过一个简单的例子(available at GitHub):

protected override void OnNavigatedFrom(NavigationEventArgs e)
{
    this.navigationHelper.OnNavigatedFrom(e);
    Debug.WriteLine("Navigation");
    this.Background = new SolidColorBrush(Colors.Red);
}

当有正常的导航(例如通过后退按钮)时，事件被触发，但当应用程序被挂起时不再触发 - 无论是在 Debug模式还是 Release模式。我还检查了是否触发了 Suspending 事件，结果是:

// uncomment this to check if app is being suspended
App.Current.Suspending += (sender, e) => this.Background = new SolidColorBrush(Colors.Blue);

我是不是漏掉了什么？

Answer 1

我唯一可以建议的是确保你调用 Frame.GetNavigationState从您的 Application.Suspending 处理程序中(这通常由 SuspensionManager.SaveAsync 完成)。根据文档:

Calling this method will call Page.OnNavigatedFrom for the current page using NavigationMode.Forward. GetNavigationState is usually called when the application is being suspended, so the current page is navigated away from.