如果我更新实体，如何进行分段更新

我的问题-如果我创建用户，在我的字段段符集-名字+姓氏。如果我更新字段名和姓，为什么没有改变?我需要为这张支票做些什么呢?因为我在路由中使用了字段(用户名)我有:

class SUser implements UserInterface
{
/**
 * @var integer
 *
 * @ORM'Column(name="id", type="integer")
 * @ORM'Id
 * @ORM'GeneratedValue(strategy="AUTO")
 */
protected $id;
/**
 * @Gedmo'Slug(fields={"firstName", "lastName"}, separator="-")
 * @ORM'Column(name="name", type="string", length=255, nullable=false)
 * @Assert'Length(min=3, max=255)
 */
protected $username;

我的形式:

class DeveloperPersonalInformationType extends AbstractType
{
/**
 * @param FormBuilderInterface $builder
 * @param array                $options
 */
public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('firstname', null, array('label' => 'First Name', 'max_length' => 255, 'required' => false))
        ->add('lastname', null, array('label' => 'Last Name', 'max_length' => 255, 'required' => false))

现在我使用自定义变体，首先在用户名中设置名和姓，但我想使用@Gedmo'Slug，如何做到这一点?我的行动:

    public function submitPersonalInformationAction($username)
    {
    $em = $this->getDoctrine()->getManager();
    $request = $this->get('request');
    $profileRepository = $this->get('artel.profile.developer.repository');
    $developer = $profileRepository->findOneByUsername($username);

    $form = $this->createForm(new DeveloperPersonalInformationType(), $developer);
    $form->handleRequest($request);
    if ($form->isValid()) 
    {
        $name = $developer->getFirstName().'-'.$developer->getLastName();
        $developer->setUsername($name);
        $em->flush();
        return $this->redirect($this->generateUrl('artel_profile_homepage', array('username' => $name)) .'#personal-information');
    }

和我的投票:

artel_profile_submit_personal_information:
path:     /profile/{username}/personal_information/submit
defaults: { _controller: ArtelProfileBundle:DeveloperProfile:submitPersonalInformation }
requirements: { _method: post }

我的配置:

stof_doctrine_extensions:
default_locale: "%locale%"
orm:
    default:
        timestampable: true
        sluggable:     true