使用表单事件提交表单的Symphony动态生成

Question

我在交响乐3.2.4中，我有3个实体：国家 - 省 - 城市。我想要动态填充3个字段。

我解释一下，我有3个字段：Country＆gt;省＆gt;城市，用户选择一个国家，省名单更新，他选择一个省，城市列表更新。

但是我有一个问题，因为只有一个字段动态更新，它是有效的，但是对于2个字段没有...实际上用户可以选择一个国家，当他这样做时，省字段会更新。但是，当他选择一个省时，城市领域没有更新......

这是我的代码：

# FormType

    ...
            $builder->addEventSubscriber(new DynamicFieldsSubscriber());
    ...
    # DynamicFieldsSubscriber

    class DynamicFieldsSubscriber implements EventSubscriberInterface
    {
        public static function getSubscribedEvents()
        {
            return array(
                FormEvents::PRE_SET_DATA => 'preSetData',
                FormEvents::PRE_SUBMIT => 'preSubmitData'
            );
        }

        public function preSetData(FormEvent $event)
        {
            $location = $event->getData();
            $form = $event->getForm();

            $country = "";
            $province = "";
            $city = "";

            if ($location) {
                // collect preliminary values for 3 fields.
                $country = $location->getEditeur();
                $prov

ince = $location->getProvince();
            $city = $location->getCity();
        }
        // Add country field as its static.
        $form
            ->add('country', EntityType::class, array(
                'class' => Editeur::class,
                'choice_label' => 'country',
                'label' => false,
                'required' => true,
                'placeholder' => 'Éditeur *',
                'empty_data' => 'Éditeur *',
                'attr' => array(
                    'class' => 'col-md-12 validate-required',
                    'placeholder' => 'Éditeur *'
                )
            ))
        ;

        // Now add all child fields.
        $this->addProvinceField($form, $country);
        $this->addCityField($form, $province);
    }

    /**
     * Handling Form fields before form submits.
     * @param FormEvent $event
     */
    public function preSubmitData(FormEvent $event)
    {
        $form = $event->getForm();
        $data = $event->getData();

        // Here $data will be in array format.

        // Add property field if parent entity data is available.
        $country = isset($data['country']) ? $data['country'] : $data['country'];
        $province = isset($data['province']) ? $data['province'] : null;
        $city = isset($data['city']) ? $data['city'] : null;

        // Call methods to add child fields.
        $this->addProvinceField($form, $country);
        $this->addCityField($form, $province);
    }

    /**
     * Method to Add State Field. (first dynamic field.)
     * @param FormInterface $form
     * @param type $country
     */
    private function addProvinceField(FormInterface $form, $country = null)
    {
        $countryCode = (is_object($country)) ? $country->getId() : $country;
        // $countryCode is dynamic here, collected from the event based data flow.
        $form
            ->add('province', EntityType::class, array(
                'class' => Province::class,
                'choice_label' => 'province',
                'label' => false,
                'required' => true,
                'placeholder' => 'Province *',
                'empty_data' => 'Province *',
                'attr' => array(
                    'class' => 'col-md-12 validate-required',
                    'placeholder' => 'Province *'
                ),
                'query_builder' => function (EntityRepository $er) use($countryCode) {
                    return $er->createQueryBuilder('p')
                        ->where('p.country = :country')
                        ->setParameter('country', $countryCode);
                }
            ))
        ;
    }

    /**
     * Method to Add District Field, (second dynamic field)
     * @param FormInterface $form
     * @param type $state
     */
    private function addCityField(FormInterface $form, $province = null)
    {
        $provinceCode = (is_object($province)) ? $province->getId() : $province;
        // $stateCode is dynamic in here collected from event based data flow.
        $form->add('city', EntityType::class, array(
            'class' => City::class,
            'choice_label' => 'city',
            'label' => false,
            'required' => true,
            'placeholder' => 'City *',
            'empty_data' => 'City *',
            'attr' => array(
                'class' => 'col-md-12 validate-required',
                'placeholder' => 'City *'
            ),
            'query_builder' => function (EntityRepository $er) use($provinceCode) {
                return $er->createQueryBuilder('e')
                    ->where('e.province = :province')
                    ->setParameter('province', $provinceCode);
            }
        ));
    }
}

## jQuery
        var $country = $('#ec_country');
        $country('change', function() {
            var $form = $(this).closest('form');
            var data = {};
            data[$country('name')] = $country();

            $.ajax({
                url : $form.attr('action'),
                type: $form.attr('method'),
                data : data,
                success: function(html) {
                    $('#ec_province').replaceWith(
                        $(html).find('#ec_province')
                    );
                }
            });
        });

        var $province = $('#ec_province');
        $(document).on('change', $province, function() {
            var $form = $(this).closest('form');
            var data = {};
            data[$programme.attr('name')] = $('#ec_province').val();

            $.ajax({
                url : $form.attr('action'),
                type: $form.attr('method'),
                data : data,
                success: function(html) {
                    $('#ec_city').replaceWith(
                        $(html).find('#ec_city')
                    );
                }
            });
        });

任何想法？感谢