如何实现NotifyPropertyChanged以检索实体更改（在带有学说的Symfony 2.8项目中）？
我找到了几个例子，但它们并不完整：
对我来说，目前尚不清楚我是否必须实现自己的onPropertyChanged函数，怎么做？我想重新检查属性更改，命名控制器中的最后一个属性和当前属性，并将它们格式化为用户的消息。
当我在文档中搜索时，NotifyPropertyChanged不会被描述或描述得最低：
http://api.symfony.com/2.8/search.html?search=NotifyPropertyChanged
http://docs.w3cub.com/symfony~2.8/
http://phpdox.de/demo/Symfony2/interfaces/Doctrine_Common_NotifyPropertyChanged.xhtml
写成addPropertyChangedListener() — Adds a listener that wants to be notified about property changes。我不明白我应该如何将自定义代码放在这个监听器中，以及如何以这种方式执行这个监听器，我可以检索实体对控制器操作的更改。
// src \ MeetingBundle \ Entity \ EventLisObject.php
<?php
namespace MeetingBundle\Entity;
use Doctrine\Common\NotifyPropertyChanged;
use Doctrine\Common\PropertyChangedListener;
abstract class EventLisObject implements NotifyPropertyChanged
{
private $listeners = array();
public function addPropertyChangedListener(PropertyChangedListener $listener) {
$this->listeners[] = $listener;
}
/** Notifies listeners of a change. */
protected function onPropertyChanged($propName, $oldValue, $newValue) {
if ($this->listeners) {
foreach ($this->listeners as $listener) {
$listener->propertyChanged($this, $propName, $oldValue, $newValue);
}
}
}
}
// C src \ MeetingBundle \ Entity \ Event.php
<?php
namespace MeetingBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;
use Symfony\Component\Validator\Constraints as Assert;
/**
* Event
*
* @ORM\Table(name="tevent", indexes={@ORM\Index(columns={"keywords"}, flags={"fulltext"})})
* @ORM\Entity(repositoryClass="MeetingBundle\Repository\EventRepository" )
*/
class Event extends EventLisObject
{
/**
* @var integer
*
* @ORM\Column(name="id", type="integer")
* @ORM\Id
* @ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* @var string
*
* @ORM\Column(name="title", type="string", length=255)
* @Assert\NotBlank()
*/
private $title;
/**
* Set title
*
* @param string $title
*
* @return Event
*/
public function setTitle($title) {
// $this->title = $title;
if( $title != $this->title ) {
$this->_onPropertyChanged("title", $this->title, $title);
$this->title = $title; }
return $this;
}
// src \ MeetingBundle \ Controller \ EventMapControllerACL.php
....
/**
* Event controller.
*
* @Route("/eventmapacl")
*/
class EventMapControllerACL extends Controller
{
/**
* @Route("/edit/{id}", name="event_jsMap_edit")
* @Method("GET|POST")
* @Template("MeetingBundle:Event:ev_jsMap_edit.html.twig")
*/
public function editAction($id, Request $request)
{
$em = $this->getDoctrine()->getManager();
$entity = $em->getRepository('MeetingBundle:Event')->find($id);
if (!$entity) {
throw $this->createNotFoundException('Unable to find Event entity.');
}
$editForm = $this->createEditForm($entity);
$editForm->handleRequest($request);
// $deleteForm = $this->createDeleteForm($id);
if ($editForm->isValid()) {
$em = $this->getDoctrine()->getManager();
$em->persist($entity);
$em->flush();
// here or before flush or before persist i would like to estimate the changes and generate the message to user informing about them.
return $this->redirect($this->generateUrl('event_jsMap_edit', array('id' => $entity->getId())));
}
return array(
'entity' => $entity,
'edit_form' => $editForm->createView(),
);
}