c＃中的WPF頁面導航＃

我想學習c＃和WPF應用程序。在這裏，我試圖在一個按鈕單擊事件上從一個WPF頁面（MainWindow.xaml）重定向到另一個（HandWash.xaml）。但是下面的代碼拋出了NULLReferenceException。這是MainWindow.xaml文件。此c＃中的WPF頁面導航＃

<Window x:Class="MyApplication.MainWindow" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    d:DesignHeight="720" d:DesignWidth="1284" 
    Title="StartPage" WindowStartupLocation="CenterScreen" WindowStyle="None" WindowState="Maximized" Closed="Window_Closed"> 
<Window.Background> 
    <ImageBrush ImageSource="/Images/StartPage.png"></ImageBrush> 
</Window.Background> 
<Grid> 
    <Button Content="Hand Wash" Height="794" HorizontalAlignment="Left" Name="HandWash" VerticalAlignment="Top" Width="353" FontSize="50" Background="Transparent" BorderThickness="0" Style="{StaticResource {x:Static ToolBar.ButtonStyleKey}}" Click="HandWash_Click"/> 
    <Button Content="Bathing" Height="794" HorizontalAlignment="Left" Margin="390,0,0,0" Name="Bathing" VerticalAlignment="Top" Width="301" FontSize="50" Background="Transparent" BorderThickness="0" Style="{StaticResource {x:Static ToolBar.ButtonStyleKey}}" Click="Bathing_Click"/> 
    <Button Content="Nail-Clip" Height="794" HorizontalAlignment="Left" Margin="730,0,0,0" Name="NailClip" VerticalAlignment="Top" Width="295" FontSize="50" Background="Transparent" BorderThickness="0" Style="{StaticResource {x:Static ToolBar.ButtonStyleKey}}" Click="NailClip_Click"/> 
    <Button Content="Teeth Brush" Height="794" HorizontalAlignment="Left" Margin="1067,0,0,0" Name="TeethBrush" VerticalAlignment="Top" Width="310" FontSize="50" Background="Transparent" BorderThickness="0" Style="{StaticResource {x:Static ToolBar.ButtonStyleKey}}" Click="TeethBrush_Click"/> 
</Grid> 
</Window>

背景代碼：

private void TeethBrush_Click(object sender, RoutedEventArgs e) 
    { 
     try 
     { 
      TeethBrush teeth = new TeethBrush(myarg); 
      NavigationService navService = NavigationService.GetNavigationService(this); 
      navService.Navigate(teeth);  // NULL REFERENCE EXCEPTION at this line 
     } 
     catch (NullReferenceException ex) 
     { 
      System.Windows.MessageBox.Show(ex.Message); 
     } 
    }

這是TeethBrush.xaml代碼：

<Page x:Class="MyApplication.TeethBrush" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    d:DesignHeight="720" d:DesignWidth="1284" 
    Title="TeethBrush"> 

<Grid> 

</Grid> 
<Page.Background> 
    <ImageBrush ImageSource="C:\Users\Tonmoy\Documents\Visual Studio 2010\Projects\MyKinectApp\MyKinectApp\Images\StartPage.png"></ImageBrush> 
</Page.Background> 

</Page>

和後臺代碼：

public TeethBrush(Myargs arg) 
    { 
     InitializeComponent(); 
     //Rest of the code 
    }

請幫助......

來源

2014-01-14 Tonmoy

是'navService'初始化？ – Loetn

是navService爲空......我該如何解決這個問題？ – Tonmoy

什麼是'NavigationService'？ – Loetn

您需要在主窗口中包含頁面內容的框架。如果將以下命名空間添加到主窗口：

xmlns:local="clr-namespace:System.Windows.Controls;assembly=PresentationFramework"

可以某處定義的框架，例如在網格：

<Grid> 
    <local:Frame x:Name="mainFrame">    
    </local:Frame> 
    ....

然後你可以從你的事件處理程序，導航，像這樣：

TeethBrush teeth = new TeethBrush(myarg); 
this.mainFrame.Navigate(teeth);

來源

2014-01-14 12:08:53 Matej

我試過這個......但是兩個WPF頁面相互重疊。我只想查看下一頁及其相應的功能。 – Tonmoy

c＃中的WPF頁面導航＃

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