Navigation zu einer anderen Windows-Telefon-Seite Fehler

Question

Ich entwickle eine Windows-App, mit der Benutzer Ice Creams bestellen können. Ich versuche, eine Schaltfläche zu einer anderen Seite namens "Logorder" zu navigieren, aber immer einen Fehler zu erhalten. Ich habe ein Bild hochgeladen, um den Fehler anzuzeigen.

-Code

Public NotInheritable Class MainPage 
Inherits Page 

Public Property NavigationService As Object 


''' <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 Overrides Sub OnNavigatedTo(e As Navigation.NavigationEventArgs) 
    ' TODO: Prepare the page for display here. 

    ' TODO: If your application contains multiple pages, ensure that you are 
    ' handling the hardware Back button by registering for the 
    ' Windows.Phone.UI.Input.HardwareButtons.BackPressed event. 
    ' If you are using the NavigationHelper provided by some templates, 
    ' this event is handled for you. 

End Sub 

Private Sub HyperlinkButton_Click(sender As Object, e As RoutedEventArgs) 

End Sub 

Private Sub button_Copy_Click(sender As Object, e As RoutedEventArgs) Handles button_Copy.Click 

    NavigationService.Navigate(New Uri("/logorder.xaml", UriKind.Relative)) 


End Sub 
End Class 

Xaml ...

<Page 
x:Class="mobileapps.MainPage" 
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
xmlns:local="using:mobileapps" 
xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
mc:Ignorable="d" 
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"> 

<Grid> 
    <Button x:Name="button_Copy" Content="Summary"  HorizontalAlignment="Left" Margin="96,425,0,0" VerticalAlignment="Top" Width="191"/> 
    <HyperlinkButton Content="HyperlinkButton" HorizontalAlignment="Left" VerticalAlignment="Top"/> 
    <HyperlinkButton Content="HyperlinkButton" HorizontalAlignment="Left" Margin="-232,186,0,0" VerticalAlignment="Top"/> 
    <HyperlinkButton Content="HyperlinkButton" HorizontalAlignment="Left" VerticalAlignment="Top"/> 
    <HyperlinkButton Content="HyperlinkButton" HorizontalAlignment="Left" VerticalAlignment="Top"/> 
    <HyperlinkButton Content="Log order" HorizontalAlignment="Left" Margin="134,332,0,0" VerticalAlignment="Top" RenderTransformOrigin="-0.106,-0.496" Click="HyperlinkButton_Click" NavigateUri="logorder.xaml"/> 
    <HyperlinkButton NavigateUri="logorder.xaml" /> 

</Grid> 

Answer 1

Sie setzen nie NavigationService, sondern versuchen, eine Methode zu nennen, so dass Sie ein NullReferenceException

bekommen

Answer 2

Versuchen Sie diese

Private Sub HyperlinkButton_Click(sender As Object, e As RoutedEventArgs) 
    Me.Frame.Navigate(GetType(BasicPage2)) 
End Sub 

How to perform navigation between pages in windows phone

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