Before calling GoForward, the CanGoForward property can be inspected to determine whether there are entries in forward navigation history.

The following example navigates to the most recent entry in forward navigation history, if one exists.

Private Sub forwardButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    If Me.NavigationService.CanGoForward Then
        Me.NavigationService.GoForward()
    End If
End Sub

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

.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