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Page.NavigationService Property

Silverlight

Other Versions

Gets the service that the host used to navigate to this page.

Namespace: System.Windows.Controls
Assembly: System.Windows.Controls.Navigation (in System.Windows.Controls.Navigation.dll)

Syntax

public NavigationService NavigationService { get; }

Property Value

Type: System.Windows.Navigation.NavigationService
The service the host used to navigate to this page.

Remarks

To navigate from within a page to either another page or another representation of the current page, you need to integrate the page navigation with the host navigation. You retrieve the host navigation for the current page through the NavigationService property.

Examples

The following example shows a Silverlight page that contains forward and back navigation buttons within the page. To determine if forward or back navigation is allowed, the page accesses the navigation service and uses its properties.

The first part of the example shows the XAML page.

XAML


<!-- NOTE: 
  By convention, the sdk prefix indicates a URI-based XAML namespace declaration 
  for Silverlight SDK client libraries. This namespace declaration is valid for 
  Silverlight 4 only. In Silverlight 3, you must use individual XAML namespace 
  declarations for each CLR assembly and namespace combination outside the scope 
  of the default Silverlight XAML namespace. For more information, see the help 
  topic "Prefixes and Mappings for Silverlight Libraries". 
-->
<sdk:Page x:Class="NavExample.Views.ProductDetail" 
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     mc:Ignorable="d"
     xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
     d:DesignWidth="640" d:DesignHeight="480"
     Title="Product Information">
    <StackPanel x:Name="LayoutRoot">
        <ListBox x:Name="ListBox1" ItemsSource="{Binding}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel>
                        <TextBlock Text="{Binding Name}"/>
                        <TextBlock Text="{Binding ProductNumber}"/>
                        <TextBlock Text="{Binding Color}"/>
                        <TextBlock Text="{Binding Size}"/>
                        <TextBlock Text="{Binding ListPrice}"/>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>   
        </ListBox>
        <StackPanel HorizontalAlignment="Center" Orientation="Horizontal">
            <Button Width="100" x:Name="BackNavButton" Click="BackNavButton_Click" 
                    Content="&lt;&lt; back" Visibility="Collapsed" />
            <Button Width="100" x:Name="ForwardNavButton" Click="ForwardNavButton_Click" 
                    Content="forward &gt;&gt;" Visibility="Collapsed" />
        </StackPanel>
    </StackPanel>
</sdk:Page>

The second part shows the code-behind page.


public partial class ProductDetail : Page
{
    public ProductDetail()
    {
        InitializeComponent();
    }

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        GetProductDetail();
        SetButtonVisibility();
    }

    private void SetButtonVisibility()
    {
        if (NavigationService.CanGoBack)
        {
            BackNavButton.Visibility = Visibility.Visible;
        }
        else
        {
            BackNavButton.Visibility = Visibility.Collapsed;
        }

        if (NavigationService.CanGoForward)
        {
            ForwardNavButton.Visibility = Visibility.Visible;
        }
        else
        {
            ForwardNavButton.Visibility = Visibility.Collapsed;
        }
    }

    private void BackNavButton_Click(object sender, RoutedEventArgs e)
    {
        if (NavigationService.CanGoBack)
        {
            NavigationService.GoBack();
        }
    }

    private void ForwardNavButton_Click(object sender, RoutedEventArgs e)
    {
        if (NavigationService.CanGoForward)
        {
            NavigationService.GoForward();
        }
    }

    private void GetProductDetail()
    {
        string productID;
        DataServiceContext svcContext = 
            new DataServiceContext(new Uri("AdventureWorks.svc", UriKind.Relative));

        if (this.NavigationContext.QueryString.ContainsKey("ProductId"))
        {
            productID = this.NavigationContext.QueryString["ProductId"];
        }
        else
        {
            productID = App.Current.Resources["FeaturedProductID"].ToString();
        }

        svcContext.BeginExecute<Product>(new Uri("Product(" + productID + ")", 
            UriKind.Relative), loadProductCallback, svcContext);
    }

    private void loadProductCallback(IAsyncResult asyncResult)
    {
        DataServiceContext context = asyncResult.AsyncState as DataServiceContext;

        ListBox1.DataContext = context.EndExecute<Product>(asyncResult);
    }
}