Symfony2表单和多态集合

Question

我正在玩Symfony2和Im abit不确定Symfony2如何在View组件中处理Polymorphic集合.看来我可以创建一个包含AbstractChildren集合的实体,但不知道如何在Form Type类中使用它.

例如,我有以下实体关系.

/**
 * @ORM\Entity
 */
class Order
{
    /**
     * @ORM\OneToMany(targetEntity="AbstractOrderItem", mappedBy="order", cascade={"all"}, orphanRemoval=true)
     * 
     * @var AbstractOrderItem $items;
     */
    $orderItems;  
    ...
}


/**
 * Base class for order items to be added to an Order
 *
 * @ORM\Entity
 * @ORM\InheritanceType("JOINED")
 * @ORM\DiscriminatorColumn(name="discr", type="string")
 * @ORM\DiscriminatorMap({
 *     "ProductOrderItem" = "ProductOrderItem",
 *     "SubscriptionOrderItem " = "SubscriptionOrderItem "
 * })
 */
class AbstractOrderItem
{
    $id;
    ...
}

/**
 * @ORM\Entity
 */
class ProductOrderItem  extends AbstractOrderItem
{
    $productName;
}

/**
 * @ORM\Entity
 */
class SubscriptionOrderItem extends AbstractOrderItem
{
    $duration;
    $startDate;
    ...
}

很简单,但是当我为我的订单类创建一个表单时

class OrderType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder->add('items', 'collection', array('type' => AbstractOrderItemType()));
    }
}

我不确定如何处理这种情况,你有效地需要为集合中的每个项目类别使用不同的表单类型？

Answer 1

我最近解决了一个类似的问题 - Symfony本身对多态集合没有任何让步,但很容易使用EventListener扩展表单来为它们提供支持.

下面是我的EventListener的内容,它使用与Symfony\Component\Form\Extension\Core\EventListener\ResizeFormListener类似的方法,该事件监听器提供集合表单类型的正常功能:

namespace Acme\VariedCollectionBundle\EventListener;

use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Form\FormFactoryInterface;
use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormEvents;

class VariedCollectionSubscriber implements EventSubscriberInterface
{
    protected $factory;
    protected $type;
    protected $typeCb;
    protected $options;

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

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

    public function fixChildTypes(FormEvent $event)
    {
        $form = $event->getForm();
        $data = $event->getData();

        // Go with defaults if we have no data
        if($data === null || '' === $data)
        {
            return;
        }

        // It's possible to use array access/addChild, but it's not a part of the interface
        // Instead, we have to remove all children and re-add them to maintain the order
        $toAdd = array();
        foreach($form as $name => $child)
        {
            // Store our own copy of the original form order, in case any are missing from the data
            $toAdd[$name] = $child->getConfig()->getOptions();
            $form->remove($name);
        }
        // Now that the form is empty, build it up again
        foreach($toAdd as $name => $origOptions)
        {
            // Decide whether to use the default form type or some extension
            $datum = $data[$name] ?: null;
            $type = $this->type;
            if($datum)
            {
                $calculatedType = call_user_func($this->typeCb, $datum);
                if($calculatedType)
                {
                    $type = $calculatedType;
                }
            }
            // And recreate the form field
            $form->add($this->factory->createNamed($name, $type, null, $origOptions));
        }
    }
}

使用这种方法的缺点是,为了识别提交时多态实体的类型,必须在绑定之前使用相关实体在表单上设置数据,否则侦听器无法确定数据的类型是.您可以使用FormTypeGuesser系统解决此问题,但这超出了我的解决方案的范围.

类似地,虽然使用此系统的集合仍支持添加/删除行,但它将假定所有新行都是基本类型 - 如果您尝试将它们设置为扩展实体,它将为您提供有关包含该表单的错误额外的字段.

为简单起见,我使用便利类型来封装此功能 - 请参阅下面的内容和示例:

namespace Acme\VariedCollectionBundle\Form\Type;

use Acme\VariedCollectionBundle\EventListener\VariedCollectionSubscriber;
use JMS\DiExtraBundle\Annotation\FormType;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\Form\AbstractType;

/**
 * @FormType()
 */
class VariedCollectionType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        // Tack on our event subscriber
        $builder->addEventSubscriber(new VariedCollectionSubscriber($builder->getFormFactory(), $options['type'], $options['type_cb']));
    }

    public function getParent()
    {
        return "collection";
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setRequired(array('type_cb'));
    }

    public function getName()
    {
        return "varied_collection";
    }
}

示例:namespace Acme\VariedCollectionBundle\Form;

use Acme\VariedCollectionBundle\Entity\TestModelWithDate;
use Acme\VariedCollectionBundle\Entity\TestModelWithInt;
use JMS\DiExtraBundle\Annotation\FormType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\Form\AbstractType;

/**
 * @FormType()
 */
class TestForm extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $typeCb = function($datum) {
            if($datum instanceof TestModelWithInt)
            {
                return "test_with_int_type";
            }
            elseif($datum instanceof TestModelWithDate)
            {
                return "test_with_date_type";
            }
            else
            {
                return null; // Returning null tells the varied collection to use the default type - can be omitted, but included here for clarity
            }
        };

        $builder->add('demoCollection', 'varied_collection', array('type_cb' => $typeCb,  /* Used for determining the per-item type */
                                                                   'type' => 'test_type', /* Used as a fallback and for prototypes */
                                                                   'allow_add' => true,
                                                                   'allow_remove' => true));
    }

    public function getName()
    {
        return "test_form";
    }
}