File symfony集合返回空文件

我有一张收款单

class EventType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('header', TextType::class, ['attr' => ['class' => 'form-control']])
                ->add('text', TextareaType::class, ['attr' => ['class' => 'form-control', 'rows' => '3']])
                ->add('fileNames', CollectionType::class, [
                    'mapped' => false,
                    'allow_add' => true,
                    'allow_delete' => true,
                    'by_reference' => false,
                    'label' => false,
                    'entry_type' => EventFileType::class,
                    ])
                ->add('save', SubmitType::class, [
                    'label' => 'Post',
                    'attr' => [
                        'class' => 'btn btn-success',
                        'style' => 'margin-top: 10px;'
                        ]
                    ]);
    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'data_class' => Event::class,
            'csrf_token_id' => 'eventToken',
            'allow_extra_fields' => true,
        ]);
    }
}

class EventFileType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('fileName', FileType::class);
    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'method' => 'POST',
            'csrf_token_id' => 'eventFiles',
        ));
    }
}

这是集合的条目类型

class EventType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('header', TextType::class, ['attr' => ['class' => 'form-control']])
                ->add('text', TextareaType::class, ['attr' => ['class' => 'form-control', 'rows' => '3']])
                ->add('fileNames', CollectionType::class, [
                    'mapped' => false,
                    'allow_add' => true,
                    'allow_delete' => true,
                    'by_reference' => false,
                    'label' => false,
                    'entry_type' => EventFileType::class,
                    ])
                ->add('save', SubmitType::class, [
                    'label' => 'Post',
                    'attr' => [
                        'class' => 'btn btn-success',
                        'style' => 'margin-top: 10px;'
                        ]
                    ]);
    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'data_class' => Event::class,
            'csrf_token_id' => 'eventToken',
            'allow_extra_fields' => true,
        ]);
    }
}

class EventFileType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('fileName', FileType::class);
    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'method' => 'POST',
            'csrf_token_id' => 'eventFiles',
        ));
    }
}

我的表格如下所示：

 {{ form_start(form, {'attr': {'id': 'form_create_event'}}) }}

                        <ul class="tags" data-prototype="{{ form_widget(form.fileNames.vars.prototype)|e('html_attr') }}">
                        </ul>
                        {{ form_end(form) }}

所以我得到文本输入，$\u文件不是空的

$form['fileNames']->getData（）

将显示文件，但字段为空，因此，如果我输入两个文件：

[{“fileName”：{}}}，{“fileName”：{}}}]

，一个文件-

[{“fileName”：{}}]

，超过3个文件显示，表单将无效。那么，我该如何让我的表单获取这些文件呢？（我不映射它们）我怎样才能得到我想要的尽可能多的文件