级联形式生成 - Symfony2

Question

我有基于Symfony2框架的网站，它有三个级别的系统。现在我想创建用于创建新产品的表单。产品还包含有关其类别，子类别以及子子类别的信息。

因此，目标是创建表单，该表单根据之前的选择自动生成子类别和子子类别的选择（当我选择类别时，生成该类别的子类别选项，当我选择子类别选项时，生成子类别）。子类别选择是正确生成的（我遵循Symfony2文档：我使用了Form Events）。我不知道如何为Subsubcategory实体正确设置事件。

这是我的代码（JavaScript工作正常，所以我跳过它）：

ProductType代码段

        $categoryFormModifer = function(FormInterface $formInterface, Category $category = null) {
        $subcategories = null == $category ? array() : $category->getSubcategories();
        $formInterface->add('idSubcategory', 'entity', array(
            'label' => "Podkategória",
            'class' => 'SalalajDefaultBundle:Subcategory',
            'choice_label' => 'subTitle',
            'placeholder' => '',
            'choices' => $subcategories,
        ));
    };

    $builder->get('idCategory')->addEventListener(
        FormEvents::POST_SUBMIT,
        function (FormEvent $event) use ($categoryFormModifer) {
            $categoryFormModifer($event->getForm()->getParent(), $event->getForm()->getData());
        }
    );

    $builder->addEventListener(
        FormEvents::PRE_SET_DATA,
        function (FormEvent $event) use ($categoryFormModifer) {
            /**
             * @var $data Product
             */
            $data = $event->getData();
            $form = $event->getForm();
            $categoryFormModifer($form, $data->getIdCategory());
            $subcategory = $data->getIdSubcategory();
            $form->add('idSubsubcategory', 'entity', array(
                'label' => "Podpodkategoria",
                'class' => 'SalalajDefaultBundle:Subsubcategory',
                'choice_label' => 'ssbTitle',
                'placeholder' => '',
                'choices' => $subcategory ? $subcategory->getIdSubsubcategory() : array()
            ));
        }
    );

    $builder->addEventListener(
        FormEvents::PRE_SUBMIT,
        function (FormEvent $event) {
            $data = $event->getData();
            $form = $event->getForm();
            /**
             * @var $subcategory Subcategory
             */
            if (!in_array('idSubcategory', $data))
                return;
            $subcategory = $data['idSubcategory'];
            $form->add('idSubsubcategory', 'entity', array(
                'label' => "Podpodkategoria",
                'class' => 'SalalajDefaultBundle:Subsubcategory',
                'choice_label' => 'ssbTitle',
                'placeholder' => '',
                'choices' => $subcategory ? $subcategory->getIdSubsubcategory() : array(),
            ));
        }
    );

感谢您的帮助！