更新狀態，城市下拉根據國家選擇Symfony

Question

我有這種關聯。國與國之間一對多。國家之間對一對多的城市。

就業形式，我必須顯示這些下拉列表，我想當我選擇一個國家，只有它相關的狀態顯示。現在它顯示所有。

這是我的表單代碼。

<?php 

namespace PNC\UsersBundle\Form; 

use Symfony\Component\Form\AbstractType; 
use Symfony\Component\Form\FormBuilderInterface; 
use Symfony\Component\OptionsResolver\OptionsResolver; 
use Symfony\Component\Form\FormBuilder; 
use Doctrine\ORM\EntityRepository; 
use Symfony\Component\Form\FormEvents; 
use Symfony\Component\Form\Event\DataEvent; 

class EmploymentsType extends AbstractType 
{ 
    public function buildForm(FormBuilderInterface $builder, array $options) 
    { 
     $builder ->add('designation', 'text', array(
        'required' => true, 
        'label' => 'Designation ', 
        'attr' => array(
         'required' => true, 
         'placeholder' => 'Designation Name', 
         'invalid_message' => 'You entered an invalid designation', 
         'class' => 'form-control' 
        ))) 
        ->add('organization', 'text', array(
        'label' => 'Organization', 
        'attr' => array(
        'required' => true, 
        'placeholder' => 'Organization Name', 
        'invalid_message' => 'You entered an invalid organization', 
        'class' => 'form-control' 
        ))) 
        ->add('country', 'entity', array(
         'label' => ucfirst('country'), 
         'class' => 'PNCGeneralBundle:Country', 
         'property'=>'name', 
         //'property_path'=>false, //Country is not directly related to City 
         'attr'=> array(
          'required' => true, 
          'invalid_message' => 'You selected an invalid Industry', 
          'class' => 'form-control' 
         ) 
        )) 
        ->add('state', 'entity', array(
         'label' => ucfirst('state'), 
         'class' => 'PNC\GeneralBundle\Entity\State', 
         'attr'=> array(
          'required' => true, 
          'invalid_message' => 'You selected an invalid Industry', 
          'class' => 'form-control' 
         ) 
        )) 
        ->add('city', 'entity', array(
         'label' => ucfirst('city'), 
         'class' => 'PNC\GeneralBundle\Entity\City', 
         'attr'=> array(
          'required' => true, 
          'invalid_message' => 'You selected an invalid Industry', 
          'class' => 'form-control' 
         ) 
        )) 
        ->add('save', 'submit', array(
         'attr' => array(
          'label' => ucfirst('save'), 
          'class' => 'btn btn-success' 
         ) 
        )); 
    } 

    public function configureOptions(OptionsResolver $resolver) 
    { 
     $resolver->setDefaults(array(
      'data_class' => 'PNC\UsersBundle\Entity\Employments', 
     )); 
    } 

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

Answer 1

我想說最簡單的方法是通過JavaScript顯示/隱藏選項。將國家，州和城市轉儲爲JSON，並將其用作JS的決策源。