A controller used to add and view a user list - http://www.symfonycentral.com/symfony-does-validation.html

UserController.php

<?php
namespace MyCompany\BlogBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Template;
use Doctrine\ORM\EntityRepository;

/* Import the entity and form classes */
use MyCompany\BlogBundle\Entity\User;
use MyCompany\BlogBundle\Form\UserType;


class UserController extends Controller
{
    /**
     * @Route("/users/", name="user_index")
     * @Template()
     */
    public function indexAction()
    {
        $users = $this->getDoctrine()
                        ->getRepository('MyCompanyBlogBundle:User')
                        ->findAll();

        return array( 'users' => $users );
    }

    /**
     * @Route("/users/new", name="user_create")
     * @Template()
     */
    public function createAction()
    {
        $user = new User();
        /* Create the form instance using the form and entity classes */
        $form = $this->createForm(new UserType(), $user);

        if ($this->getRequest()->getMethod() == "POST") {
            /* On postback, bind the form values to the form object */
            $form->bind($this->getRequest()->get($form->getName()));

            if ($form->isValid()) {
                /* If the assertions pass, we can persist the object... */
                $em = $this->getDoctrine()->getEntityManager();
                $em->persist($user);
                $em->flush();

                /* ... and redirect */
                $this->redirect(
                    $this->generateUrl('user_index')
                );
            }
        }

        /* Otherwise show the form again. Any errors that were
         * triggered by isValid() will be displayed 
         */
        return array('form' => $form->createView());
    }
}