Many-to-many relationship inside a symfony 3 form - many-to-many

Question

I have a problem implementing a symfony 3 form with two objects having a many-to-many relationship.
I have two datatables, "Users" and "Roles". I want to have a form, where I can edit a user and assign a user some roles. In detail I want a form where each Role is a checkbox and I can choose which role a user has.
I know, that I have to implement a new UserType,, but how can I implement the dynamic checkboxes?
This is my User-Class:
<?php
// src/AppBundle/Entity/User.php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Security\Core\User\UserInterface;
/**
* #ORM\Table(name="app_users")
* #ORM\Entity(repositoryClass="AppBundle\Entity\UserRepository")
*/
class User implements UserInterface, \Serializable
{
/**
* #ORM\Column(type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\Column(type="string", length=25, unique=true)
*/
private $username;
/**
* #ORM\Column(type="string", length=64)
*/
private $password;
/**
* #ORM\Column(type="string", length=60, unique=true)
*/
private $email;
/**
* #ORM\Column(name="is_active", type="boolean")
*/
private $isActive;
/**
* #ORM\ManyToMany(targetEntity="Role", inversedBy="users")
* #ORM\JoinTable(name="user_roles")
*/
private $roles;
public function __construct()
{
$this->isActive = true;
// may not be needed, see section on salt below
// $this->salt = md5(uniqid(null, true));
}
public function getUsername()
{
return $this->username;
}
public function getSalt()
{
// you *may* need a real salt depending on your encoder
// see section on salt below
return null;
}
public function getPassword()
{
return $this->password;
}
public function getRoles()
{
$permissionsArray = array();
foreach ($this->roles as $role)
{
$rolesPermissions = $role->getPermissions();
for($i=0;$i<count($rolesPermissions);$i++)
if(!in_array($rolesPermissions[$i],$permissionsArray))
$permissionsArray[] = $rolesPermissions[$i];
}
return $permissionsArray;
}
public function eraseCredentials()
{
}
/** #see \Serializable::serialize() */
public function serialize()
{
return serialize(array(
$this->id,
$this->username,
$this->password,
// see section on salt below
// $this->salt,
));
}
/** #see \Serializable::unserialize() */
public function unserialize($serialized)
{
list (
$this->id,
$this->username,
$this->password,
// see section on salt below
// $this->salt
) = unserialize($serialized);
}
/**
* Get id
*
* #return integer
*/
public function getId()
{
return $this->id;
}
/**
* Set username
*
* #param string $username
*
* #return User
*/
public function setUsername($username)
{
$this->username = $username;
return $this;
}
/**
* Set password
*
* #param string $password
*
* #return User
*/
public function setPassword($password)
{
$this->password = $password;
return $this;
}
/**
* Set email
*
* #param string $email
*
* #return User
*/
public function setEmail($email)
{
$this->email = $email;
return $this;
}
/**
* Get email
*
* #return string
*/
public function getEmail()
{
return $this->email;
}
/**
* Set isActive
*
* #param boolean $isActive
*
* #return User
*/
public function setIsActive($isActive)
{
$this->isActive = $isActive;
return $this;
}
/**
* Get isActive
*
* #return boolean
*/
public function getIsActive()
{
return $this->isActive;
}
}
And this is my Role-Class:
<?php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* Role
*
* #ORM\Table(name="role")
* #ORM\Entity(repositoryClass="AppBundle\Repository\RoleRepository")
*/
class Role
{
/**
* #var int
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var string
*
* #ORM\Column(name="bezeichnung", type="string", length=255, unique=true)
*/
private $bezeichnung;
/**
* #ORM\ManyToMany(targetEntity="User", mappedBy="roles")
*/
private $users;
/**
* #ORM\ManyToMany(targetEntity="Permission", inversedBy="roles")
* #ORM\JoinTable(name="roles_permissions")
*/
private $permissions;
/**
* Get id
*
* #return int
*/
public function getId()
{
return $this->id;
}
/**
* Set bezeichnung
*
* #param string $description
*
* #return Role
*/
public function setBezeichnung($bezeichnung)
{
$this->bezeichnung = $bezeichnung;
return $this;
}
/**
* Get bezeichnung
*
* #return string
*/
public function getBezeichnung()
{
return $this->bezeichnung;
}
/**
* Constructor
*/
public function __construct()
{
$this->users = new \Doctrine\Common\Collections\ArrayCollection();
$this->roles = new \Doctrine\Common\Collections\ArrayCollection();
}
/**
* Add user
*
* #param \AppBundle\Entity\User $user
*
* #return Role
*/
public function addUser(\AppBundle\Entity\User $user)
{
$this->users[] = $user;
return $this;
}
/**
* Remove user
*
* #param \AppBundle\Entity\User $user
*/
public function removeUser(\AppBundle\Entity\User $user)
{
$this->users->removeElement($user);
}
/**
* Get users
*
* #return \Doctrine\Common\Collections\Collection
*/
public function getUsers()
{
return $this->users;
}
/**
* Add permission
*
* #param \AppBundle\Entity\Permission $permission
*
* #return Role
*/
public function addPermission(\AppBundle\Entity\Permission $permission)
{
$this->permissions[] = $permission;
return $this;
}
/**
* Remove permission
*
* #param \AppBundle\Entity\Permission $permission
*/
public function removePermission(\AppBundle\Entity\Permission $permission)
{
$this->permissions->removeElement($permission);
}
/**
* Get permissions
*
* #return Array
*/
public function getPermissions()
{
$permissionsArray = array();
foreach ($this->permissions as $permission)
$permissionsArray[] = "ROLE_".$permission->getTechBezeichnung();
return $permissionsArray;
}
}

Answer 1

a) Give your entities a __toString() method.
b) Make a UserType. You can also Use the CLI command bin/console doctrine:generate:crud and choose at "write actions" [yes].
The script wil generate a controller, a formType and some templates.
c) add this use statement at the top of UserType:
use Symfony\Bridge\Doctrine\Form\Type\EntityType;
d) add this formfield into your UserType:
->add('roles', EntityType::class, array(
'expanded => true,
'multiple' => true
))