• Статья

Frame.CanGoBack Property

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Gets a value that indicates whether there is at least one entry in the back navigation history.

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

Syntax

'Declaration
Public Property CanGoBack As Boolean

public bool CanGoBack { get; internal set; }

Property Value

Type: System.Boolean
true if there is at least one entry in the back navigation history; otherwise, false.

Remarks

Dependency property identifier field: CanGoBackProperty

The GoBack method throws an InvalidOperationException exception if there are no entries in the back navigation history. To determine whether there is at least one entry in the back navigation history, check the value of the CanGoBack property.

Examples

The following example shows event handler code for buttons on a frame that allow forward and back navigation.

Private Sub BackNavButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    If (ContentFrame.CanGoBack) Then
        ContentFrame.GoBack()
    End If
End Sub

Private Sub ForwardNavButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    If (ContentFrame.CanGoForward) Then
        ContentFrame.GoForward()
    End If
End Sub

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

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

Version Information

Silverlight

Supported in: 5, 4, 3

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.