Concatenate properties in Symfony2 buildForm() - php

Question

I have a set of entities in Doctrine which depends on each other to build certain data, and I need to create a form which uses data from two of those entities.
I have a Magazine entity, an Issue entity and a Chapter entity. The Magazine (Mag1, Mag2) has it's name, the Issue, that belongs to only one Magazine, has it's 'number' (Mag1->Issue 1, Mag1->Issue 2, Mag3-> Issue 1, Mag2 -> Issue 'Summer'). The Chapter have to belong to just one Issue, but when creating the form, to build the Issue selector I need to concatenate properties from two entities:
class ChapterType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('name')
->add('number')
->add('issue', 'entity', array(
'class' => 'Bundle:Issue',
'property' => 'magazine.name'
))
;
}
...
What I need to do is concatenate in the 'property' something like 'magazine.name'+'number' (where 'number' is the Issue which will be added number. Trying to concatenate with the . like in php strings doesn't work since they aren't strings so I don't know what I have to do or if It's possible to do It this way.

Answer 1

In the Issue create a new getter that does the concat. Given that you have properly setup the ManyToOne relationship, the getter should be something like:
public function getMagazzineAndIssue() {
return $this->magazine->getName() . $this->number;
}
in the form, use this new method as the property:
$builder
->add('name')
->add('number')
->add('issue', 'entity', array(
'class' => 'Bundle:Issue',
'property' => 'magazineAndIssue'
))