c#之如何从 gecko webbrowser 控件 ,"i want to disable view source in browser"中删除上下文菜单项

private void geckoWebBrowser1_ShowContextMenu(object sender, GeckoContextMenuEventArgs e) 
{ 
     if (e.ContextMenu.GetContextMenu().MenuItems.RemoveAt("view in system ) 
     { 
 
     }                 
}