表单文件上传验证-不使用form-> createView（）

Question

我正在尝试在其中具有FileUpload类型的Symfony4控制器中验证表单。 HTML表单不是用$form->createView()生成的。

$form->isSubmitted()始终为假，因为除非执行此操作，否则它不会在请求中看到文件：

$request->request->set("imageFile", $request->files->get('imageFile'));

$form->submit($request->request->all());

简单的HTML表单：

<form style="background-color: #00acc1" method="POST" enctype="multipart/form-data" action="{{ path('user_api_brand_image_upload') }}">
  <input type="file" name='imageFile' />
  <input type="hidden" name='_token' value="{{ csrf_token('user_api_brand_image_upload') }}" />
  <input type=submit value="upload img now">
</form>

控制器：

$formBuilder = $this->createFormBuilder(null, [
        'allow_extra_fields' => true, 
        'csrf_field_name' => '_token', 
        'csrf_token_id' => 'user_api_brand_image_upload'
    ])->add('imageFile', FileType::class, [
            'required' => true,
            'mapped' => false,
            'constraints' => [
                new NotBlank(['message' => 'Image is required and must be less than 10MB.']),
                new Image([
                    'maxSize' => '10M'
                ])        
            ]
        ]
    );


$form = $formBuilder->getForm();

...

//Always false 
 $form->isSubmitted()

//Unless I do this first
//$request->request->set("imageFile", $request->files->get('imageFile'));
//$form->submit($request->request->all());