How to clear WebBrowser control in WPF

I found this. Anyone have anything better?

if (wb != null)
{
    if (e.NewValue != null)
        wb.NavigateToString(e.NewValue as string);
    else
        wb.Navigate("about:blank");
}

EDIT:

As poby mentioned in the comments, for .NET 4+ use:

if (wb != null)
{
    if (e.NewValue != null)
        wb.NavigateToString(e.NewValue as string);
    else
        wb.Navigate((Uri)null);
}