Symfony 2.7中的依賴窗體錯誤：非對象上的getId（）

Question

我想用自定義查詢生成器創建使用Symfony 2.7的依賴窗體，但是PRE_SUBMIT不斷實例化錯誤的對象。

我上傳了github的部分數據sampleData.sql。

CityType

public function buildForm(FormBuilderInterface $builder,array$options){ 

    $builder->add('country', 'entity', array(
     'class' => 'TestMyBundle:Country', 
     'choice_label' => 'country' 
    )); 
    $builder->add('Search','submit'); 

    $stateFormbuilder = function(FormInterface $form,$country_Id){ 
     $search = $form->get('Search'); 
     $form->remove('Search'); 
     $form->add('state','entity',array(
      'class'=>'TestMyBundle:State', 
      'query_builder'=>function(EntityRepository $repository) use ($country_Id){ 
       return $repository->createQueryBuilder('State') 
            ->where('State.countryId= :countryId') 
            ->setParameter('countryId',$country_Id) 
            ->orderBy('State.state','ASC') 
            ; 
      } 
     )); 
    }; 
    $CityFormbuilder = function(FormInterface $form, $state_Id){ 
     $form->add('city','entity',array(
      'class'=>'TestMyBundle:City', 
      'query_builder'=>function(EntityRepository $repository) use ($state_Id){ 
       return $repository->createQueryBuilder('City') 
            ->where('City.countryId= :countryId') 
            ->setParameter('City.stateId',$state_Id) 
            ->orderBy('City.city','ASC') 
            ; 
      } 
     )); 
    }; 
    $CityAreaFormBuilder = function(FormInterface $form, $city_Id){ 
     $form->add('cityArea','entity',array(
      'class'=>'TestMyBundle:CityArea', 
      'query_builder'=>function(EntityRepository $repository) use ($city_Id){ 
       return $repository->createQueryBuilder('CityArea') 
        ->where('CityArea.city= :cityId') 
        ->setParameter('CityArea.cityId',$city_Id) 
        ->orderBy('CityArea.cityArea','ASC') 
        ; 
      } 
     )); 
     $form->add('Search','submit'); 
    }; 
    //$CityFormbuilder, $CityAreaFormBuilder 
    //$builder->add('Search', 'submit'); 
    // State 
    $builder->addEventListener(FormEvents::PRE_SET_DATA, function(FormEvent $event) use($stateFormbuilder) { 
     $country = $event->getData(); 
     $country_id = null; 
     if(null!== $country){ 
      $country_id = $country->getId(); 
     } 
     $stateFormbuilder($event->getForm(),$country_id); 
    }); 
    $builder->addEventListener(FormEvents::PRE_SUBMIT,function(FormEvent $event) use($stateFormbuilder){ 
     $data = $event->getData(); 
     $country_id = array_key_exists('id',$data) ? $data['id']:null; 
     $stateFormbuilder($event->getForm(),$country_id); 
    }); 
    // City 
    $builder->addEventListener(FormEvents::PRE_SET_DATA, function(FormEvent $event) use($CityFormbuilder) { 
     $state = $event->getData(); 
     $stateId = null; 
     if(null!==$state){ 
      $stateId = $state->getId(); 
     } 
     $CityFormbuilder($event->getForm(),$stateId); 
    }); 
    $builder->addEventListener(FormEvents::PRE_SUBMIT,function(FormEvent $event) use($CityFormbuilder){ 
     $data = $event->getData(); 
     $city_id = array_key_exists('id',$data) ? $data['id']:null; 
     $CityFormbuilder($event->getForm(),$city_id); 
    }); 
    // City Area 
    $builder->addEventListener(FormEvents::PRE_SET_DATA, function(FormEvent $event) use($CityAreaFormBuilder) { 
     $cityArea = $event->getData(); 
     $cityAreaId = null; 
     if(null!==$cityArea){ 
      $cityAreaId= $cityArea->getId(); 
     } 
     $CityAreaFormBuilder($event->getForm(),$cityAreaId); 
    }); 
    $builder->addEventListener(FormEvents::PRE_SUBMIT,function(FormEvent $event) use($CityAreaFormBuilder){ 
     $data = $event->getData(); 
     $cityArea_Id = array_key_exists('id',$data) ? $data['id']:null; 
     $CityAreaFormBuilder($event->getForm(),$cityArea_Id); 
    }); 
} 

My Stack Trace

Error: Call to a member function getId() on a non-object

Answer 1

如圖documentation說，如果沒有數據被傳遞給形式，$event->getData()爲空。

對於您的每3個EventListener S的使用了PRE_SET_DATA事件，
添加下面的檢查（我把最後一個事件爲例）：

$state = $event->getData(); 
$stateId = null; 

if (null !== $state) { 
    $stateId = $state->getId(); 
} 

然後，根據價值做你的邏輯$stateId。