symfony - symfony2链式选择器

Question

我有三个实体:国家，州和城市，具有以下关系:


创建城市时，我需要两个选择器，一个用于城市，一个用于城市所属的州。这两个选择器需要链接在一起，因此更改“国家”将“过滤”另一个选择器中显示的国家。
我发现了一个tutorial，它显示了如何使用表单事件来执行此操作，但是他们的示例并不是我的情况。我的实体城市与国家(地区)实体没有直接关系(它们通过州(State)间接关联)，因此，当在城市(CityType)类中设置国家(地区)字段时，我被迫将该字段声明为'property_path'=>false参见下面的代码:

class CityType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder->add('country', 'entity', array(
            'class'=>'TestBundle:Country', 
            'property'=>'name', 
            'property_path'=>false //Country is not directly related to City
        ));
        $builder->add('name');

        $factory = $builder->getFormFactory();

        $refreshStates = function ($form, $country) use ($factory) 
        {
            $form->add($factory->createNamed('entity', 'state', null, array(
                'class'         => 'Test\TestBundle\Entity\State',
                'property'      => 'name',
                'query_builder' => function (EntityRepository $repository) use ($country)
                                   {
                                       $qb = $repository->createQueryBuilder('state')
                                                        ->innerJoin('state.country', 'country');

                                        if($country instanceof Country) {
                                            $qb->where('state.country = :country')
                                               ->setParameter('country', $country);
                                        } elseif(is_numeric($country)) {
                                            $qb->where('country.id = :country')
                                               ->setParameter('country', $country);
                                        } else {
                                            $qb->where('country.name = :country')
                                               ->setParameter('country', "Venezuela");;
                                        }        
                                        return $qb;
                                    }
            )));
        };

        $builder->addEventListener(FormEvents::PRE_SET_DATA, function (DataEvent $event) use ($refreshStates)
        {
            $form = $event->getForm();
            $data = $event->getData();

            if($data == null)
                return;               

            if($data instanceof City){
                if($data->getId()) { //An existing City
                    $refreshStates($form, $data->getState()->getCountry());
                }else{               //A new City
                    $refreshStates($form, null);
                }
            }
        });

        $builder->addEventListener(FormEvents::PRE_BIND, function (DataEvent $event) use ($refreshStates)
        {
            $form = $event->getForm();
            $data = $event->getData();

            if(array_key_exists('country', $data)) {
                $refreshStates($form, $data['country']);
            }
        });
    }

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

    public function getDefaultOptions(array $options)
    {
        return array('data_class' => 'Test\TestBundle\Entity\City');
    }
}

问题是，当我尝试编辑现有城市时，默认情况下不会在表格中选择相关的国家(地区)。如果删除行 'property_path'=>false，我会收到(错误地)错误消息:
类“Test \ TestBundle \ Entity \ City”中既不存在属性“country”，也不存在方法“getCountry()”或方法“isCountry()”
有任何想法吗？

Answer 1

好的，我终于想出了正确的做法:

namespace Test\TestBundle\Form;

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

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

use Test\TestBundle\Entity\Country;
use Test\TestBundle\Entity\State;
use Test\TestBundle\Entity\City;


class CityType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder->add('name');

        $factory = $builder->getFormFactory();

        $refreshStates = function ($form, $country) use ($factory) {
            $form->add($factory->createNamed('entity','state', null, array(
                'class'         => 'Test\TestBundle\Entity\State',
                'property'      => 'name',
                'empty_value'   => '-- Select a state --',
                'query_builder' => function (EntityRepository $repository) use ($country) {
                    $qb = $repository->createQueryBuilder('state')
                        ->innerJoin('state.country', 'country');

                    if ($country instanceof Country) {
                        $qb->where('state.country = :country')
                            ->setParameter('country', $country);
                    } elseif (is_numeric($country)) {
                        $qb->where('country.id = :country')
                            ->setParameter('country', $country);
                    } else {
                        $qb->where('country.name = :country')
                            ->setParameter('country', null);
                    }

                    return $qb;
               })
           ));
        };

        $setCountry = function ($form, $country) use ($factory) {
            $form->add($factory->createNamed('entity', 'country', null, array(
                'class'         => 'TestBundle:Country', 
                'property'      => 'name', 
                'property_path' => false,
                'empty_value'   => '-- Select a country --',
                'data'          => $country,
            )));
        };

        $builder->addEventListener(FormEvents::PRE_SET_DATA, function (DataEvent $event) use ($refreshStates, $setCountry) {
            $form = $event->getForm();
            $data = $event->getData();

            if ($data == null) {
                return;
            }

            if ($data instanceof City) {
                $country = ($data->getId()) ? $data->getState()->getCountry() : null ;
                $refreshStates($form, $country);
                $setCountry($form, $country);
            }
        });

        $builder->addEventListener(FormEvents::PRE_BIND, function (DataEvent $event) use ($refreshStates) {
            $form = $event->getForm();
            $data = $event->getData();

            if(array_key_exists('country', $data)) {
                $refreshStates($form, $data['country']);
            }
        });
    }

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

    public function getDefaultOptions(array $options)
    {
        return array('data_class' => 'Test\TestBundle\Entity\City');
    }
}

jQuery AJAX选择器

$(document).ready(function () {
    $('#city_country').change(function(){
        $('#city_state option:gt(0)').remove();
        if($(this).val()){
            $.ajax({
                type: "GET",
                data: "country_id=" + $(this).val(),
                url: Routing.generate('state_list'),
                success: function(data){
                    $('#city_state').append(data);
                }
            });
        }
    });
});

我希望这将对面临相同情况的其他人有所帮助。