symfony - 表单提交问题

Question

我想创建新用户并从组合框中给他一个角色，但它在这里不起作用是我到目前为止所做的：

角色形式

class RoleType extends AbstractType
{
        /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('role','entity',array(
                    'class' => 'vendor\Bundle\Entity\Role',
                    'property'=>'role'
                ))
        ;
    }

用户表格

class UserType extends AbstractType
{
        /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('username')
            ->add('password')
            ->add('email')
            ->add('firstname')
            ->add('lastname')
            ->add('role',new RoleType())
        ;
    }

但我无法将我的用户保存到数据库我收到此错误

执行 'UPDATE Roles SET role = 时发生异常？WHERE role_id = ?' 带参数 [{}, 1]：

控制器

  private function createEditForm(User $entity)
    {
        $form = $this->createForm(new UserType(), $entity, array(
            'action' => $this->generateUrl('user_update', array('id' => $entity->getId())),
            'method' => 'PUT',
        ));

        $form->add('submit', 'submit', array('label' => 'Update'));

        return $form;
    }
    /**
     * Edits an existing User entity.
     *
     */
    public function updateAction(Request $request, $id)
    {
        $em = $this->getDoctrine()->getManager();

        $entity = $em->getRepository('myBundle:User')->find($id);

        if (!$entity) {
            throw $this->createNotFoundException('Unable to find User entity.');
        }

        $deleteForm = $this->createDeleteForm($id);
        $editForm = $this->createEditForm($entity);
        $editForm->handleRequest($request);

        if ($editForm->isValid()) {
            $em->flush();

            return $this->redirect($this->generateUrl('user_edit', array('id' => $id)));
        }

        return $this->render('myBundle:User:edit.html.twig', array(
            'entity'      => $entity,
            'edit_form'   => $editForm->createView(),
            'delete_form' => $deleteForm->createView(),
        ));
    }

Answer 1

为什么不直接在 UserType 构建器中定义角色字段？

class UserType extends AbstractType
{
        /**
     * @param FormBuilderInterface $builder
     * @param array $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('username')
            ->add('password')
            ->add('email')
            ->add('firstname')
            ->add('lastname')
            ->add('role','entity',array(
                'class' => 'vendor\Bundle\Entity\Role',
                'property'=>'role'
            ))
        ;
    }