我已经找到了吧!
如果有人需要解决同样的问题，这里是我的解决方案。
胶片控制器：

/**
     * @Route("/film/update", name="film_update")
     */
    public function updateAction(Request $request)
    {

        $films = array('films' => $this->getDoctrine()->getRepository('LfayBundle:Film\Film')->findAll()) ;
        $forms = $this->createForm(FilmContainerType::class, $films);

        $forms->handleRequest($request);
        if ($forms->isSubmitted() && $forms->isValid()) {

            $em = $this->getDoctrine()->getManager();
            //$em->persist($films_all);
            $em->flush();

            return $this->redirectToRoute('film_update');
        }

        return $this->render(
          'film/film_update.html.twig',
          array(
            'forms' => $forms->createView(),
          )
        );
    }

胶片容器类型：

class FilmContainerType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
          ->add('films', CollectionType::class, array(
          'entry_type' => FilmType::class));
    }

    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
          'data_class' => null
        ));
    }

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

胶片类型：

class FilmType extends AbstractType
{
    /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
          ->add('style', TextType::class)
          ->add('director', TextType::class)
          ->add('actor', TextType::class)
        ;
    }

    /**
     * @param OptionsResolver $resolver
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'xxxxBundle\Entity\Film\Film'
        ));
    }
}

电影更新. html. twig

{% block content %}
    <div class="row">
        <div class="col-sm-12">
            <div class="box box-solid box-primary">
                <div class="box-header with-border">
                    <h3 class="box-title">Liste des applications</h3>
                    <div class="box-tools pull-right">
                        <button class="btn btn-box-tool" data-widget="collapse"><i class="fa fa-minus"></i></button>
                    </div><!-- /.box-tools -->
                </div><!-- /.box-header -->
                <div class="box-body">
                     <div class="dataTables_wrapper form-inline dt-bootstrap">
                        {{ form_start(forms) }}
                        <table class="table table-bordered table-hover dataTable" id="all_applications" width="100%">
                            <thead>
                            <tr>
                                <th>Film</th>
                                <th>acteur</th>
                                <th>realisateur</th>
                                <th>autre</th>
                            </tr>
                            </thead>
                            <tbody>
                            {% for film in forms.films %}
                                {{ form_errors(film) }}
                                   <tr>
                                    <td>{{ film.vars.value.name }}</td>
                                    <td>{{ form_widget(film.style, {'attr': {'class': 'c-select'}}) }}</td>
                                    <td>{{ form_widget(film.director, {'attr': {'class': 'c-select'}}) }}</td>
                                    <td>{{ form_widget(film.actor, {'attr': {'class': 'c-select'}}) }}</td>
                                </tr>
                            {% endfor %}
                             </tbody>
                        </table>
                         <button type="submit" class="btn btn-primary btn-lg btn-block">Modifier</button>
                         {{ form_end(forms) }}
                        <div>

                    </div>
                    </div>
                </div>
            </div>
        </div>
     </div><!-- row --> 
{% endblock %}

就这样。