如何使用表单编辑symfony 2中的用户权限？

我在symfony 2 FOSUserBundle中创建新的/编辑用户表单时遇到问题 . 我想让管理员从下拉列表或单选按钮列表中选择用户角色，但我似乎无法让它工作 . 我在这里找到了这个答案How can I pass a full security roles list/hierarchy to a FormType class in Symfony2?这是我能找到的最相关的东西，但它不起作用 .

这是目前的UserType表单 . 我想从容器中获取角色但我可以't seem to get that to work either without it throwing an error. The roles will populate the dropdown properly but it will not show which role is currently assigned and it won' t允许更新信息，因为它期望它是一个数组 $entity->addRoles(array('ROLE_SUPER_ADMIN')); ，但它只是作为字符串提交 .

namespace Wes\AdminBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class UserType extends AbstractType
{
    private $roles;

    public function __construct($roles) {
        $this->roles = $roles;
    }

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('username')
            ->add('email')
            ->add('enabled')
            ->add('roles', 'choice', array(
               'choices' => $this->flattenArray($this->roles),
            ))
            ->add('firstName')
            ->add('lastName')
        ;
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'Wes\AdminBundle\Entity\User',
            'roles' => null,
            'userRole' => null,
        ));
    }

    public function getName()
    {
        return 'wes_adminbundle_usertype';
    }

    private function flattenArray(array $data)
    {
        $returnData = array();

        foreach($data as $key => $value)
        {
            $tempValue = str_replace("ROLE_", '', $key);
            $tempValue = ucwords(strtolower(str_replace("_", ' ', $tempValue)));
            $returnData[$key] = $tempValue;
        }
        return $returnData;
    }
}

这是控制器 .

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

    $entity = $em->getRepository('WesAdminBundle:User')->find($id);
    if (!$entity) {
        throw $this->createNotFoundException('Unable to find User entity.');
    }

    $editForm = $this->createForm(new UserType($this->container->getParameter('security.role_hierarchy.roles')), $entity);
    $deleteForm = $this->createDeleteForm($id);

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

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

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

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

    $deleteForm = $this->createDeleteForm($id);
    $editForm = $this->createForm(new UserType($this->container->getParameter('security.role_hierarchy.roles')), $entity);
    $editForm->bind($request);

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

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

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

我已经打了几天了，我似乎无法让它正常工作 . 有什么想法吗？