通过AJAX的Symfony Form FileType：验证错误isSubmitted（）始终为false，因为processData：false

我过去用 AJAX JQUERY 完成了文件上传，但现在我正在尝试用symfony FileType 做同样的事情 .

问题是在正常工作流程中我们需要添加 contentType: false, processData: false, 但这似乎导致以下symfony错误： Cannot check if an unsubmitted form is valid. Call Form::isSubmitted() before Form::isValid().

所以 isSubmitted() 总是假的，我猜是因为 processData: false

我完全失去了如何解决这个问题，因为如果我不做 contentType: false ，那么AJAX请求会崩溃 . symfony文档对此不满意 .

JAVASCRIPT：

const form_data = $('#newBrandForm').serializeArray();
const json = serializeAsObject(form_data)

    const files = document.getElementById('new_brand_group_logo_logoFile').files;

    if (files.length > 0) {

        let formData = new FormData();

        for (let x = 0; x < files.length; x++) {
            formData.append("attachements", files[x]);
        }

        json['new_brand[group_logo][logoFile]'] = formData

    }

    $.ajax({
        url: `/new-brand-form-handle`,
        type: 'POST',
        cache: false,
        contentType: false,
        processData: false,
        data: json
    })

CONTROLLER

function brandFormHandle(Request $request) {

    $em = $this->getDoctrine()->getManager();

    $brandEntity = new Brand();

    // create form
    $form = $this->createForm(NewBrandType::class, $brandEntity);

    // handle
    $form->handleRequest($request); // CRASH HERE

    if ($form->isSubmitted() && $form->isValid()) { 

        $brand = $form->getData();

        // move file
        $someNewFilename = 'newBrand'.'-logo';
        $file = $form['attachment']->getData();
        $file->move($this->directory, $someNewFilename);

        try {

            $em->persist($brand);
            $em->flush();

            $status = 'Brand added';

        } catch (Exception $ex) {
            return $this->json([2, 'insertion error'.$ex]);
        }
        return $this->json([1, $status]);
    }

 //....

}

$request DUMP所以我可以看到那里的文件，但看起来表单只是一个对象，所以我不确定这是不是问题？

Request {#51 ▼
+attributes: ParameterBag {#71 ▶}
+request: ParameterBag {#87 ▼
#parameters: array:1 [▼
  "form" => "[object Object]"
]
}
+query: ParameterBag {#70 ▶}
+server: ServerBag {#35 ▶}
+files: FileBag {#73 ▶}
+cookies: ParameterBag {#72 ▶}
+headers: HeaderBag {#82 ▶}
#content: null
#languages: null
#charsets: null
#encodings: null
#acceptableContentTypes: null
#pathInfo: "/new-brand-form-handle"
#requestUri: "/new-brand-form-handle"
#baseUrl: ""
#basePath: null
#method: "POST"
#format: null
#session: Closure {#111 ▶}
#locale: null
#defaultLocale: "en"
-isHostValid: true
-isForwardedValid: true
basePath: ""
format: "html"
}

//这是来自console.log（json）的转储，注意没有文件;我不确定这是否正常

Object
 new_brand[group_description][description]: "description"
 new_brand[group_identification][city]: ""
 new_brand[group_identification][country]: "AU"
 new_brand[group_identification][name]: "name"
 new_brand[group_identification][postcode]: ""
 new_brand[group_identification][streetAdd]: ""
 new_brand[group_identification][street]: "street"
 new_brand[group_identification][website]: "website"
 new_brand[group_logo][logoURL]: "web"