Symfony2 Form - 嵌入表单和事件监听器

Question

我有一个带有事件侦听器的表单“AddressType”，它在单独实例化时按预期工作。这是代码。

namespace Nc\ClientsBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;
use Nc\ClientsBundle\Form\EventListener\AddCityFieldSubscriber;

class AddressType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder
            ->add('street')
            ->add('number', 'text')
            ->add('complement')
            ->add('district')
            ->add('state', 'entity', array(
                'class' => 'ClientsBundle:State', 
                'property' => 'name',
            ));
        $subscriber = new AddCityFieldSubscriber($builder->getFormFactory());
        $builder->addEventSubscriber($subscriber);
    }

    public function getDefaultOptions(array $options)
    {
        return array(
            'data_class' => 'Nc\ClientsBundle\Entity\Address',
        );
    }

    public function getName()
    {
        return 'addresstype';
    }
}


<?php

namespace Nc\ClientsBundle\Form\EventListener;

use Symfony\Component\Form\Event\DataEvent;
use Symfony\Component\Form\FormFactoryInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Form\FormEvents;
use Doctrine\ORM\EntityRepository;

class AddCityFieldSubscriber implements EventSubscriberInterface
{
    private $factory;

    public function __construct(FormFactoryInterface $factory)
    {
        $this->factory = $factory;
    }

    public static function getSubscribedEvents()
    {
        // Tells the dispatcher that we want to listen on the form.pre_set_data
        // event and that the preSetData method should be called.
        return array(FormEvents::PRE_SET_DATA  => 'preSetData');
    }

    public function preSetData(DataEvent $event)
    {
        $data = $event->getData();
        $form = $event->getForm();

        // During form creation setData() is called with null as an argument
        // by the FormBuilder constructor. We're only concerned with when
        // setData is called with an actual Entity object in it (whether new,
        // or fetched with Doctrine). This if statement let's us skip right
        // over the null condition.
        if (null === $data) {
            return;
        }

        if (!$data->getCity()) {

            $form->add($this->factory->createNamed('city_selector', 'city', null, array(
                'choices'   => array('' => '--  Selecione um estado  --'),
                'required'  => true,
                'expanded'  => false,
                'multiple'  => false,
            )));

        } else {

            $city = $data->getCity();
            $form->add($this->factory->createNamed('city_selector', 'city', null, array(
                'choices'   => array($city->getId() => $city->getName()),
                'required'  => true,
                'expanded'  => false,
                'multiple'  => false,
            )));
        }

    }

}

<?php

namespace Nc\ClientsBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

use Doctrine\Common\Persistence\ObjectManager;
use Nc\ClientsBundle\Form\DataTransformer\CityToIdTransformer;

class CitySelectorType extends AbstractType
{
    /**
     * @var ObjectManager
     */
    private $om;

    /**
     * @param ObjectManager $om
     */
    public function __construct(ObjectManager $om)
    {
        $this->om = $om;
    }

    public function buildForm(FormBuilder $builder, array $options)
    {
        $transformer = new CityToIdTransformer($this->om);
        $builder->prependNormTransformer($transformer);
    }

    public function getDefaultOptions(array $options)
    {
        return array(
            'invalid_message' => 'Selecione um estado e uma cidade.',
        );
    }

    public function getParent(array $options)
    {
        return 'choice';
    }

    public function getName()
    {
        return 'city_selector';
    }
}

<?php

namespace Nc\ClientsBundle\Form\DataTransformer;

use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;
use Doctrine\Common\Persistence\ObjectManager;
use Nc\ClientsBundle\Entity\City;

class CityToIdTransformer implements DataTransformerInterface
{
    /**
     * @var ObjectManager
     */
    private $om;

    /**
     * @param ObjectManager $om
     */
    public function __construct(ObjectManager $om)
    {
        $this->om = $om;
    }

    /**
     * Transforms an object (city) to a integer (id).
     *
     * @param  City|null $city
     * @return string
     */
    public function transform($city)
    {
        if ($city === null) {
            return '';
        }

        return $city->getId();

    }

    /**
     * Transforms a string (id) to an object (city).
     *
     * @param  string $id
     * @return City|null
     * @throws TransformationFailedException if object (city) is not found.
     */
    public function reverseTransform($id)
    {
        if (!$id) {
            return null;
        }

        $city = $this->om
            ->getRepository('ClientsBundle:City')
            ->findOneBy(array('id' => $id))
        ;

        if (null === $city) {
            throw new TransformationFailedException(sprintf(
                'An city with id "%s" does not exist!',
                $id
            ));
        }

        return $city;
    }
}

发生的情况是，当我尝试将此表单嵌入“ClientType”表单时，“city”字段未呈现。

namespace Nc\ClientsBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilder;

class ClientType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder->add('name');
        $builder->add('type', 'choice', array(
            'choices'   => array('1' => 'Comum', '2' => 'Parceiro'),
            'expanded'  => true,
            'multiple'  => false,
            'required'  => true,
        ));
        $builder->add('contactInfo', new ContactInfoType(), array('label' => ' '));
        $builder->add('address', new AddressType(), array('label' => ' '));
    }

    public function getDefaultOptions(array $options)
    {
        return array(
            'data_class' => 'Nc\ClientsBundle\Entity\Client',
        );
    }

    public function getName()
    {
        return 'clienttype';
    }
}

Answer 1

当您尝试嵌入城市字段并且实体没有填充城市值时，方法$form->getData()返回null，因此在这种情况下城市字段不会呈现，因为“if”语句总是返回false（订阅者类中的 preSetData 函数） 首先我们要检查是否填写了城市，如果是则添加相应的表单字段，否则添加空白字段（或其他）。

这里有一些代码sn-ps：

1. 如果填写了城市字段，则添加城市字段

   public function preSetData(DataEvent $event)
   {
       $data = $event->getData();
       $form = $event->getForm();
   
       if (!($data instanceof Address) || !$data->getCity()) {
           return;
       }
   
       $city = $data->getCity();
       $form->add($this->factory->createNamed('city_selector', 'city', null, array(
           'choices'   => array($city->getId() => $city->getName()),
           'required'  => true,
           'expanded'  => false,
           'multiple'  => false,
       )));
   }
   

2. 如果值未填写则添加空白城市字段（postSetData在设置数据后触发）

   public function postSetData(DataEvent $event)
   {
       $form = $event->getForm();
   
       if (!$form->has('city_selector')) {
           $form->add($this->factory->createNamed('city_selector', 'city', null, array(
               'choices'   => array('' => '--  Selecione um estado  --'),
               'required'  => true,
               'expanded'  => false,
               'multiple'  => false,
           )));
       }
   }
   

3. 我们还要注册 postSetData 事件

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