我正在處理網(wǎng)站的登錄頁(yè)面。當(dāng)我單擊登錄按鈕時(shí)沒有任何反應(yīng)，但是當(dāng)我 $form->isValid() 從代碼中刪除時(shí)它工作正常。經(jīng)過幾次測(cè)試，我發(fā)現(xiàn) $form->isValid() 總是返回 false！我不明白為什么總是這樣false！這是控制器的代碼：/** * @Route("/login", name="login", methods={"GET","POST"}) */public function login(Request $request): Response{    $user = new Admins();    $form = $this->createFormBuilder($user)    ->add('username', TextType::class)    ->add('password', PasswordType::class)    ->getForm();        $form->handleRequest($request);    if ($form->isSubmitted() && $form->isValid()) {        $session =$request->getSession();        $session->clear();        $username =$user->getUsername();        $password =$user->getPassword();        $repository = $this->getDoctrine()->getRepository(Admins::class);        $user1=$repository->findOneBy(array('username'=>$username,'password'=>$password));        if (!$user1)          {              $this->get('session')->getFlashBag()->add('info','The username or password is incorrect');}        else         {            if (!$session->has('name'))            {                $session->set('username',$user1->getUsername());                $session->set('rank',$user1->getRank());                return $this->redirectToRoute('homepage');                         }                    }                }    return $this->render('login/index.html.twig', [        'user' => $user,        'form' => $form->createView(),    ]);}這是查看頁(yè)面的代碼：<div class="text-center w-full p-t-25 p-b-50">    {% if app.session.flashBag.has('info') %}        <div class="btn btn-warning">            {% for msg in app.session.flashBag.get('info') %}                {{msg}}            {% endfor %}        </div>    {% endif %}</div><form id="accesspanel" action=" {{ path ('login') }} " method="post">    <h1 id="litheader">Login Panel    </h1>