Question

以下代码

use Application\Events\TransactionCreatedEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\EventDispatcher\EventDispatcher;

class Transaction implements EventSubscriberInterface
{
    protected $date;
    protected $name;
    protected $address;
    protected $phone;
    protected $price_with_vat;
    protected $transaction_type;
    protected $receipt;
    protected $currency;


    protected function __construct($date, $name, $address, $phone, $price_with_vat, $transaction_type, $receipt, $currency)
    {
        $dispatcher = new EventDispatcher();
        $dispatcher->addSubscriber($this);
        $dispatcher->dispatch(TransactionCreatedEvent::NAME, new TransactionCreatedEvent($date, $name, $address, $phone, $price_with_vat, $transaction_type, $receipt, $currency));
    }

    public static function CreateNewTransaction($date, $name, $address, $phone, $price_with_vat, $transaction_type, $receipt, $currency){
        return new Transaction($date, $name, $address, $phone, $price_with_vat, $transaction_type, $receipt, $currency);
    }

    private function onCreateNewTransaction($Event){
        $this->date = $Event->date;
        $this->name = $Event->name;
        $this->address = $Event->address;
        $this->phone = $Event->phone;
        $this->price_with_vat = $Event->price_with_vat;
        $this->transaction_type = $Event->transaction_type;
        $this->receipt = $Event->receipt;
        $this->currency = $Event->currency;
    }

    public static function getSubscribedEvents()
    {
        return array(TransactionCreatedEvent::NAME => 'onCreateNewTransaction');
    }
}

它假设派遣一个TransactionCreated事件并被类本身捕获，并且onCreatedNewTransaction函数调用以设置类的属性。

Transaction类实例化为

$Transaction = Transaction::CreateNewTransaction('6/6/2016', 'John'....);

但是当我调试项目时，$Transaction对象的值为null。我在breakpoint方法设置onCreateNewTransaction，我发现因此不会调用函数。

已更新

问题解决了

`onCreateNewTransaction'应该是公开的而不是私人的

Answer 1

您的方法CreateNewTransaction是静态的，因此不会创建Transaction的实例，因此永远不会调用__constructor。

这就是为什么这段代码无效。

但是，除此之外，我必须说它完全滥用了Event Symfony系统。使用框架（无EventDispatcher组件），您不能自己创建EventDispatcher。它是由FrameworkBundle创建的，您应该只将event_dispatcher服务注入到您需要的任何内容中。

否则，您可能会在不同的范围内（每个调度员拥有自己的订阅者和它自己的事件）很快迷失方向，而且，＆＃39;是浪费资源。

Symfony EventDispatcher订户不工作

1 个答案: