When either a WebException or an IOException is thrown during a navigation, the NavigationFailed event is raised. NavigationFailed is passed a NavigationFailedEventArgs that encapsulates information about both the exception and the details of the navigation that caused the exception.

When an exception results from a failed navigation, and is unhandled, the following events are raised in the order listed:

• NavigationService..::.NavigationFailed.

• Frame..::.NavigationFailed or NavigationWindow..::.NavigationFailed.

• Application..::.NavigationFailed.

• DispatcherUnhandledException.

If a navigator (NavigationWindow, Frame) is hosted by one or more navigators, NavigationFailed is not raised on any of them.

The following example shows how to handle NavigationFailed.

Private Sub NavigationService_NavigationFailed(ByVal sender As Object, ByVal e As NavigationFailedEventArgs)
    Dim msg As String = String.Format("Navigation to {0} failed: {1}.", e.Uri.OriginalString, e.Exception.Message)
    Me.progressStatusBarItem.Content = msg
End Sub

void NavigationService_NavigationFailed(object sender, NavigationFailedEventArgs e)
{
    string msg = string.Format("Navigation to {0} failed: {1}.", e.Uri.OriginalString, e.Exception.Message);
    this.progressStatusBarItem.Content = msg;
}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference