Symfony フレームワークでフォーム イベント (Form Events) 処理ロジックを使用する方法

use SymfonyComponentFormAbstractType;
use SymfonyComponentFormFormBuilderInterface;
use SymfonyComponentOptionsResolverOptionsResolver;
use SymfonyComponentFormFormEvent;
use SymfonyComponentFormFormEvents;

class RegistrationType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('username', TextType::class)
            ->add('email', EmailType::class);
            
        // 添加一个事件监听器
        $builder->addEventListener(FormEvents::POST_SUBMIT, [$this, 'onPostSubmit']);
    }
    
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'data_class' => User::class
        ]);
    }
    
    // 定义一个事件处理方法
    public function onPostSubmit(FormEvent $event)
    {
        // 在这里执行自定义逻辑
        $formData = $event->getData();
        $form = $event->getForm();
        
        // 获取用户名和电子邮件字段的值
        $username = $formData['username'];
        $email = $formData['email'];
        
        // 执行逻辑 ...
    }
}

use AppFormRegistrationType;

class UserController extends AbstractController
{
    public function register(Request $request)
    {
        $user = new User();
        $form = $this->createForm(RegistrationType::class, $user);
        
        $form->handleRequest($request);
        
        if ($form->isSubmitted() && $form->isValid()) {
            // 表单数据有效，执行自定义逻辑
        }
        
        return $this->render('register.html.twig', [
            'form' => $form->createView(),
        ]);
    }
}