后退按钮关闭应用程序，而不是在 Windows Phone 8.1 上返回答案

【问题标题】：Back button closing app instead of going back on Windows Phone 8.1后退按钮关闭应用程序，而不是在 Windows Phone 8.1 上返回
【发布时间】：2015-06-20 10:00:52
【问题描述】：

我在 Visual Studio 2013 中创建了一个简单的 Windows Phone 8.1 应用程序，并添加了 2 个基本页面，以及一些用于在单击第一个屏幕上的按钮时导航到第二个屏幕的代码。转到第二个屏幕可以正常工作，但是当按下硬件后退按钮时，应用程序只会关闭。我希望应用程序在按下“返回”按钮时返回到第一页。

我已经按照NavigationHelper.vb 中的说明添加了带有一些初始化命令的Sub New()，但是“返回”按钮仍然不起作用。我怎样才能按 Back 才能正常工作？提前致谢。

这是我的代码：

BasicPage1.xaml.vb:

Imports App1.Common

Public NotInheritable Class BasicPage1
    Inherits Page

    Private WithEvents _navigationHelper As New NavigationHelper(Me)
    Private ReadOnly _defaultViewModel As New ObservableDictionary()

    Public ReadOnly Property NavigationHelper As NavigationHelper
        Get
            Return _navigationHelper
        End Get
    End Property

    Sub New()

        InitializeComponent()

        Me._navigationHelper = New Common.NavigationHelper(Me)
        AddHandler Me._navigationHelper.LoadState, AddressOf NavigationHelper_LoadState
        AddHandler Me._navigationHelper.SaveState, AddressOf NavigationHelper_SaveState
    End Sub

    Public ReadOnly Property DefaultViewModel As ObservableDictionary
        Get
            Return _defaultViewModel
        End Get
    End Property

    Private Sub NavigationHelper_LoadState(sender As Object, e As LoadStateEventArgs) Handles _navigationHelper.LoadState
    End Sub

    Private Sub NavigationHelper_SaveState(sender As Object, e As SaveStateEventArgs) Handles _navigationHelper.SaveState
    End Sub

#Region "NavigationHelper registration"

    Protected Overrides Sub OnNavigatedTo(e As NavigationEventArgs)
        _navigationHelper.OnNavigatedTo(e)
    End Sub

    Protected Overrides Sub OnNavigatedFrom(e As NavigationEventArgs)
        _navigationHelper.OnNavigatedFrom(e)
    End Sub

#End Region

    Private Sub button_Click(sender As Object, e As RoutedEventArgs) Handles Button.Click
        Frame.Navigate(GetType(BasicPage2))
    End Sub
End Class

BasicPage2.xaml.vb:

Imports App1.Common

Public NotInheritable Class BasicPage2
    Inherits Page

    Private WithEvents _navigationHelper As New NavigationHelper(Me)
    Private ReadOnly _defaultViewModel As New ObservableDictionary()

    Public ReadOnly Property NavigationHelper As NavigationHelper
        Get
            Return _navigationHelper
        End Get
    End Property

    Sub New()

        InitializeComponent()

        Me._navigationHelper = New Common.NavigationHelper(Me)
        AddHandler Me._navigationHelper.LoadState, AddressOf NavigationHelper_LoadState
        AddHandler Me._navigationHelper.SaveState, AddressOf NavigationHelper_SaveState
    End Sub

    Public ReadOnly Property DefaultViewModel As ObservableDictionary
        Get
            Return _defaultViewModel
        End Get
    End Property

    Private Sub NavigationHelper_LoadState(sender As Object, e As LoadStateEventArgs) Handles _navigationHelper.LoadState
    End Sub

    Private Sub NavigationHelper_SaveState(sender As Object, e As SaveStateEventArgs) Handles _navigationHelper.SaveState
    End Sub

#Region "NavigationHelper registration"

    Protected Overrides Sub OnNavigatedTo(e As NavigationEventArgs)
        _navigationHelper.OnNavigatedTo(e)
    End Sub

    Protected Overrides Sub OnNavigatedFrom(e As NavigationEventArgs)
        _navigationHelper.OnNavigatedFrom(e)
    End Sub

#End Region

End Class

完整的解决方案在这里：https://github.com/OrangeFlash81/SimpleWPApp

【问题讨论】：

标签： vb.net xaml windows-phone-8.1

【解决方案1】：

我自己通过使用AddHandler 添加事件处理程序并使用Frame.Navigate 返回第一页来解决了这个问题。我添加了这段代码：

Sub New()
    AddHandler HardwareButtons.BackPressed, AddressOf BackPressed
End Sub

Sub BackPressed(sender As Object, e As BackPressedEventArgs)
    e.Handled = True
    Frame.Navigate(GetType(BasicPage1))
End Sub

【讨论】：