在symfony中添加带有表单事件的字段

Question

I try add fields with form events in symfony but fields is add automaticly when refresh page ... scenario is when I fill input email fields body is display ...

code PostType:

<?php

    namespace AppBundle\Form;

    use Symfony\Component\Form\AbstractType;
    use Symfony\Component\Form\FormBuilderInterface;
    use Symfony\Component\OptionsResolver\OptionsResolver;
    use Symfony\Component\Form\Extension\Core\Type\SubmitType;
    use Symfony\Component\Form\FormEvent;
    use Symfony\Component\Form\FormEvents;

    class PostType extends AbstractType
    {
        /**
         * {@inheritdoc}
         */
        public function buildForm(FormBuilderInterface $builder, array $options)
        {
            $builder->add('titl')->add('email')->add('phone');
            $builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event){
                $post = $event->getData();
                $form = $event->getForm();
                   if(!empty($post->getEmail))
                   {
                     $form->add('body');
                   }

                });
            $builder->add('save', SubmitType::class);
        }/**
         * {@inheritdoc}
         */
        public function configureOptions(OptionsResolver $resolver)
        {
            $resolver->setDefaults(array(
                'data_class' => 'AppBundle\Entity\Post'
            ));
        }

        /**
         * {@inheritdoc}
         */
        public function getBlockPrefix()
        {
            return 'appbundle_post';
        }


    }

help me please and thanks for advanced

Answer 1

as it says in comment you have to use Javascript to do this, for example make an ajax request to submit the form and to apply, always in javascript, the HTML response.

There is a great video tutorial for this (in french) https://www.youtube.com/watch?v=F0Z-D3MSjA0&t=1504s