Entity mapping in a Symfony2 choice field with optgroup
entities, forms, symfony
Solution
Here follows my solution. Notice that it is not mentioned in the Symfony2 official docs, but it works! I exploited the fact that the entity field type is child of `choice`.
Hence, you can just pass the array of `choices` as a param.
$builder->add('bestfriend', 'entity', array(
'class' => 'AcmeHelloBundle:User',
'choices' => $this->getArrayOfEntities()
));
where the function `getArrayOfEntities()` is a function that fills the choice list with the friends of my friends, organized by my friends:
private function getArrayOfEntities(){
$repo = $this->em->getRepository('AcmeHelloBundle:User');
$friends = $repo->findAllFriendByComplexCriteria(...);
$list = array();
foreach($friends as $friend){
$name = $friend->getUsername();
if(count($friend->getFriends())>0){
$list[$name] = array();
foreach($friend->getFriends() as $ff){
$list[$name][$ff->getUsername()] = $ff;
}
}
}
return $list;
}
I know the example could be meaningless, but it works...
PS: You need to pass the entity manager to let it working...
Problem
Suppose to have an entity in Symfony2 that has a field `bestfriend`, which is a `User` entity selected from a list of `User` entities that satisfy a complex requirement. You can render this field in a form by specifying that it is an entity field type, i.e.: ``` $builder->add('bestfriend', 'entity', array( 'class' => 'AcmeHelloBundle:User', 'property' => 'username', )); ``` This form field is rendered as a `<select>`, where each one of the displayed values is in the form: ``` <option value="user_id">user_username</option> ``` So, one would render the field by using the `<optgroup>` tags to highlight such special feature of the friends. Following this principle, I created a field type, namely `FriendType`, that creates the array of choices as in this answer, which is rendered as follows: ``` $builder->add('bestfriend', new FriendType(...)); ``` The `FriendType` class creates a `<select>` organized with the same `<option>`s but organized under `<optgroup>`s. Here I come to the problem! When submitting the form, the framework recognize that the user field is not an instance of User, but it is an integer. How can I let Symfony2 understand that the passed int is the id of an entity of type User?