c# - 当应用程序暂停时，不会调用 OnNavigateFrom

Question

今天我遇到了奇怪的问题 - 似乎在我的设备(v. 8.10.14203.306)上，当应用程序暂停时，OnNavieratedFrom 事件没有被调用。据我记得前段时间它工作正常，而且完全正确as documentation stays :

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

我尝试了一个简单的示例( available at GitHub ):

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

当正常导航(例如通过后退按钮)时，事件会被触发，但当应用程序暂停时(无论是在调试还是 Release模式下)都不会再触发。我还检查了 Suspending 事件是否被触发，结果是:

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

我错过了什么吗？

Answer 1

我唯一可以建议的是确保您调用 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.