Symfony2 Ajax上传

I'm trying to upload files with ajax calls, but when I go to save my saves only the relationship with anagrafic. I state that if I try to save normally work correctly.

It is as if it not loaded the object UploadFile! I created the table according to the symfony cookbook http://symfony.com/doc/2.1/cookbook/doctrine/file_uploads.html In my controller

public function fileCreateAction($id)
{
    $em = $this->getDoctrine()->getManager();

    $entity = $em->getRepository('MyBusinessBundle:Anagrafic')->find($id);
    $media = new Multimedia();
    $form = $this->createForm(new MultimediaType(), $media);

    if ($this->getRequest()->isMethod('POST')) {
        $form->bind($this->getRequest());
        if ($form->isValid()) {
            $em = $this->getDoctrine()->getManager();

            $media->setAnagrafic($entity);
            $em->persist($media);
            $em->flush();

            $response = new Response();
        $output = array('success' => true);
        $response->headers->set('Content-Type', 'application/json');
        $response->setContent(json_encode($output));
        }
    }

I tried to do a var_dump of var_dump($media); and return:

object(My\BusinessBundle\Entity\Multimedia)[337]
  private 'id' => null
  private 'percorso' => null
  private 'alt' => null
  private 'type' => null
  public 'file' => null
  private 'anagrafic' => null

I don't understand why.. but if I use a plug-in jquery https://github.com/blueimp/jQuery-File-Upload to pass the file, I get the correct file that I can continue with the method of the cookbook! my solution:

public function fileCreateAction($id)
{
    $em = $this->getDoctrine()->getManager();

    $entity = $em->getRepository('MyBusinessBundle:Anagrafic')->find($id);
    $media = new Multimedia();
    $form = $this->createForm(new MultimediaType(), $media);

    $request = $this->getRequest();
    if ($request->isMethod('POST')) {
        $form->bind($request);
        if ($form->isValid()) {
            $em = $this->getDoctrine()->getManager();
            $media->setAnagrafic($entity);
            $em->persist($media);
            $em->flush();

            if ($request->isXmlHttpRequest()) {
                $response = new Response();
                $output = array('success' => true);
                $response->headers->set('Content-Type', 'application/json');
                $response->setContent(json_encode($output));

                return $response;
            } else {
                return $this->redirect($this->generateUrl('user_img', array('id' => $entity->getId())));
            }

    } else {
    if ($request->isXmlHttpRequest()) {
        $errors = $form->get('file')->getErrors();
        $response = new Response();
        $output = array('success' => false, 'errors' => $errors[0]->getMessage());
        $response->headers->set('Content-Type', 'application/json');
        $response->setContent(json_encode($output));

        return $response;
    }
    }
    }

would be to refactor given the double call -> isXmlHttpRequest (), but the concept works! I forgot .. if you set the input file as "multiple" a request is made for each file!

Solved!