我試圖從另外一個添加到一個的SimpleXMLElement，但我得到的錯誤： Warning: SimpleXMLElement::addChild(): Cannot add child. Parent is not a permanent member of the XML tree $xml = $Global->serializeTradeShowTable();
$xmlDeser
我有問題。我添加了一個新的服務PopupListener.php： use Symfony\Bundle\FrameworkBundle\Routing\Router;
use Symfony\Component\DependencyInjection\ContainerInterface;
class PopupListener
{
protected $router;