Symfony2的表单事件 FormEventSubscriber

Form事件是动态处理表单动作的一种方式，在buildForm方法里添加Subscriber:

<?php
namespace Demo\AdminBundle\Form\Type;
use Symfony\Component\Form\FormBuilderInterface;
use FOS\UserBundle\Form\Type\RegistrationFormType as BaseType;
class RegistrationFormType extends BaseType
{
 private $doctrine;
 public function __construct( $class , \Doctrine\Bundle\DoctrineBundle\Registry $doctrine)
 {
 parent::__construct( $class);
 $this->doctrine = $doctrine;
 }
 public function buildForm( FormBuilderInterface $builder , array $option )
 {
 parent::buildForm($builder, $option);
 $builder->add('name')
 ;
 //这里传递FormFactory到监听器里 用来修改表单
 $subscriber = new \Mc\AdminBundle\EventListener\FormSetDataListener($builder->getFormFactory());
 //添加subscriber
 $builder->addEventSubscriber( $subscriber);
 }
 ...

然后写一下Subscriber :

<?php
namespace Demo\AdminBundle\EventListener;
use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormFactoryInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Form\FormEvents;
class FormSetDataListener implements EventSubscriberInterface
{
 private $factory;
 public function __construct( FormFactoryInterface $factory)
 {
 $this->factory = $factory;
 }
 public static function getSubscribedEvents()
 {
 return array( FormEvents::POST_SET_DATA => 'postSetData');
 }
 public function postSetData( FormEvent $event )
 { 
 $form = $event->getForm();
 $data = $event->getData();
 if( null == $data)
 {
 return ;
 }
 //这里我的操作是移除原先的密码框 然后手动给它填充数据 data的数据是从另外一个表单传递到这个表单来的 (基于FOSUserBundle做的一个分步注册的功能 俗称form wizard) 这个数据来源直接在FormFactory获取就好了 
 //这样等于在这里重建了一下form
 $form->remove('plainPassword');
 $form->add('plainPassword', 'repeated', array(
 'data' => $data->getPassword() , 
 'type' => 'text',
 'options' => array('translation_domain' => 'FOSUserBundle'),
 'first_options' => array('label' => 'form.password'),
 'second_options' => array('label' => 'form.password_confirmation'),
 'invalid_message' => 'fos_user.password.mismatch',
 )
 );
 }
}

到这里一个form监听事件就完成了
这里的

 public static function getSubscribedEvents()
 {
 return array( FormEvents::POST_SET_DATA => 'postSetData');
 }

还有几个事件 分别是form的不同时期 都是可以通过监听来修改它的状态:

<?php
/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Symfony\Component\Form;
/**
 * @author Bernhard Schussek <bschussek@gmail.com>
 */
final class FormEvents
{
 const PRE_SUBMIT = 'form.pre_bind';
 const SUBMIT = 'form.bind';
 const POST_SUBMIT = 'form.post_bind';
 const PRE_SET_DATA = 'form.pre_set_data';
 const POST_SET_DATA = 'form.post_set_data';
 /**
 * @deprecated Deprecated since version 2.3, to be removed in 3.0. Use
 * {@link PRE_SUBMIT} instead.
 */
 const PRE_BIND = 'form.pre_bind';
 /**
 * @deprecated Deprecated since version 2.3, to be removed in 3.0. Use
 * {@link SUBMIT} instead.
 */
 const BIND = 'form.bind';
 /**
 * @deprecated Deprecated since version 2.3, to be removed in 3.0. Use
 * {@link POST_SUBMIT} instead.
 */
 const POST_BIND = 'form.post_bind';
 private function __construct()
 {
 }
}

至于每个事件的先后顺序 可以在form一系列的定义里都可以看到。