C# 如何在Windows Phone 8.1上仅浏览一页
伙计。我正在手机应用程序中努力导航。我已经在我的项目中添加了三个空白页面，并设法在页面之间导航，但是。。。。 我希望一个用户在点击手机上的“后退按钮”时只返回一页，当然，当他再次按下按钮时，返回主页。发生的情况是，用户在按下设备上的后退按钮时退出应用程序。 这是我在名为：C# 如何在Windows Phone 8.1上仅浏览一页,c#,windows,xaml,windows-phone-8.1,C#,Windows,Xaml,Windows Phone 8.1,伙计。我正在手机应用程序中努力导航。我已经在我的项目中添加了三个空白页面，并设法在页面之间导航，但是。。。。 我希望一个用户在点击手机上的“后退按钮”时只返回一页，当然，当他再次按下按钮时，返回主页。发生的情况是，用户在按下设备上的后退按钮时退出应用程序。 这是我在名为： private void HardwareButtons_BackPressed(object sender, Windows.Phone.UI.Input.BackPressedEventArgs e) {
private void HardwareButtons_BackPressed(object sender, Windows.Phone.UI.Input.BackPressedEventArgs e)
{
if (this.GoBackCommand.CanExecute(null))
{
e.Handled = true;
this.GoBackCommand.Execute(null);
}
}
if (Frame.CanGoBack)
{
e.Handled = true;
Frame.GoBack();
}
// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkID=390556
namespace NutriPal
{
/// <summary>
/// An empty page that can be used on its own or navigated to within a Frame.
/// </summary>
public sealed partial class ListPage : Page
{
public ListPage()
{
this.InitializeComponent();
}
/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached.
/// This parameter is typically used to configure the page.</param>
protected override void OnNavigatedTo(NavigationEventArgs e)
{
BrowsingManager browsing = (BrowsingManager) e.Parameter as BrowsingManager;
if (browsing != null)
{
listOfItems.DataContext = browsing;
//pageTitle.Text = browsing.Title;
}
}
public class NavigationHelper : DependencyObject
{
private Page Page { get; set; }
private Frame Frame { get { return this.Page.Frame; } }
/// <summary>
/// Initializes a new instance of the <see cref="NavigationHelper"/> class.
/// </summary>
/// <param name="page">A reference to the current page used for navigation.
/// This reference allows for frame manipulation and to ensure that keyboard
/// navigation requests only occur when the page is occupying the entire window.</param>
public NavigationHelper(Page page)
{
this.Page = page;
// When this page is part of the visual tree make two changes:
// 1) Map application view state to visual state for the page
// 2) Handle hardware navigation requests
this.Page.Loaded += (sender, e) =>
{
#if WINDOWS_PHONE_APP
Windows.Phone.UI.Input.HardwareButtons.BackPressed += HardwareButtons_BackPressed;
#else
// Keyboard and mouse navigation only apply when occupying the entire window
if (this.Page.ActualHeight == Window.Current.Bounds.Height &&
this.Page.ActualWidth == Window.Current.Bounds.Width)
{
// Listen to the window directly so focus isn't required
Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated +=
CoreDispatcher_AcceleratorKeyActivated;
Window.Current.CoreWindow.PointerPressed +=
this.CoreWindow_PointerPressed;
}
#endif
};
// Undo the same changes when the page is no longer visible
this.Page.Unloaded += (sender, e) =>
{
#if WINDOWS_PHONE_APP
Windows.Phone.UI.Input.HardwareButtons.BackPressed -= HardwareButtons_BackPressed;
#else
Window.Current.CoreWindow.Dispatcher.AcceleratorKeyActivated -=
CoreDispatcher_AcceleratorKeyActivated;
Window.Current.CoreWindow.PointerPressed -=
this.CoreWindow_PointerPressed;
#endif
};
}
public void OnNavigatedTo(NavigationEventArgs e)
{
var frameState = SuspensionManager.SessionStateForFrame(this.Frame);
this._pageKey = "Page-" + this.Frame.BackStackDepth;
if (e.NavigationMode == NavigationMode.New)
{
// Clear existing state for forward navigation when adding a new page to the
// navigation stack
var nextPageKey = this._pageKey;
int nextPageIndex = this.Frame.BackStackDepth;
while (frameState.Remove(nextPageKey))
{
nextPageIndex++;
nextPageKey = "Page-" + nextPageIndex;
}
// Pass the navigation parameter to the new page
if (this.LoadState != null)
{
this.LoadState(this, new LoadStateEventArgs(e.Parameter, null));
}
}
公共类NavigationHelper:DependencyObject
{
专用页页面{get；set；}
私有帧帧{get{返回this.Page.Frame；}}
///
///初始化类的新实例。
///
///对用于导航的当前页面的引用。
///此参考允许进行帧操作，并确保键盘
///导航请求仅在页面占用整个窗口时发生。
公共NavigationHelper（第页）
{
this.Page=Page；
//当此页面是可视化树的一部分时，请进行两项更改：
//1）将应用程序视图状态映射到页面的可视状态
//2）处理硬件导航请求
this.Page.Loaded+=（发件人，e）=>
{
#如果WINDOWS\u PHONE\u应用程序
Windows.Phone.UI.Input.HardwareButtons.BackPressed+=硬件按钮\u BackPressed；
#否则
//键盘和鼠标导航仅在占用整个窗口时适用
如果（this.Page.ActualHeight==Window.Current.Bounds.Height&&
this.Page.ActualWidth==Window.Current.Bounds.Width）
{
//直接收听窗口，因此无需聚焦
Window.Current.CoreWindow.Dispatcher.AcceleratoryActivated+=
CoreDispatcher_加速器已激活；
Window.Current.CoreWindow.Pointer已压缩+=
此.core窗口_指针已压缩；
}
#恩迪夫
};
//当页面不再可见时，撤消相同的更改
this.Page.unload+=（发件人，e）=>
{
#如果WINDOWS\u PHONE\u应用程序
Windows.Phone.UI.Input.HardwareButtons.BackPressed-=HardwareButtons\u BackPressed；
#否则
Window.Current.CoreWindow.Dispatcher.AcceleratoryActivated-=
CoreDispatcher_加速器已激活；
Window.Current.CoreWindow.Pointer已压缩-=
此.core窗口_指针已压缩；
#恩迪夫
};
}
导航到时的公共无效（导航目标e）
{
var frameState=SuspensionManager.SessionStateForFrame（this.Frame）；
这。_pageKey=“Page-”+this.Frame.backbackbackdepth；
if（e.NavigationMode==NavigationMode.New）
{
//将新页面添加到页面时，清除前进导航的现有状态
//导航堆栈
var nextPageKey=此项。_pageKey；
int nextPageIndex=this.Frame.BackStackDepth；
while（frameState.Remove（nextPageKey））
{
nextPageIndex++；
nextPageKey=“Page-”+nextPageIndex；
}
//将导航参数传递到新页面
if（this.LoadState！=null）
{
this.LoadState（this，new LoadStateEventArgs（e.Parameter，null））；
}
}
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
NavigationService.Navigate(new Uri("PageName", UriKind.Relative));
base.OnBackKeyPress(e);
}
应用程序从第二页或主页退出？你能检查一下你订阅了多少次HardwareButtons_BackPressed吗？（在app.xaml.cs中也检查一下）。还请检查是否使用NavigationHelper。我的应用程序使用的主页是从第二页和第三页开始的。我的主页中有公用文件夹和NavigationHelper。据我所知，有一个订阅：Windows.Phone.UI.Input.HardwareButtons.BackPressed+=HardwareButtons\u BackPressed；你能检查你的页面是否使用NavigationHelper吗（应该有
this.NavigationHelper=new NavigationHelper；protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
NavigationService.Navigate(new Uri("PageName", UriKind.Relative));
base.OnBackKeyPress(e);
}