Question

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，以及在单击第一个屏幕上的按钮时导航到第二个屏幕的一些代码。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，应用程序就会关闭。我希望应用程序在按下“返回”按钮时返回第一页。

我已按照NavigationHelper.vb中的说明添加了Sub New()并添加了一些初始化命令，但“后退”按钮仍无效。我怎样才能按下返回正常工作？提前谢谢。

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

Answer 1

我通过使用AddHandler添加事件处理程序并使用Frame.Navigate返回第一页来自行解决问题。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

后退按钮关闭应用程序而不是返回Windows Phone 8.1

1 个答案: