How get field value in form builder in Symfony - php

Question

How to get field value in form builder in Symfony.
I have 2 Dropdowns in the form
I want to should the related option in Dropdown2 based on Dropdown1 in when the Page is Opening.
Here is My Form
use Symfony\Component\Form\FormEvents;
use Symfony\Component\Form\Event\DataEvent;
use C2Educate\ToolsBundle\Entity\Students;
public function buildForm(FormBuilder $builder, array $options) {
Field 1:
$builder->add('leadSource', 'entity', array(
'label' => 'How did you hear about C2? Source ',
'class' => 'C2EducateToolsBundle:LeadSources',
'query_builder' => function($repo) {
return $repo->createQueryBuilder('p')->orderBy('p.sort_order', 'ASC');
},
'property' => 'name',
'empty_value' => 'Select'
));
$leadSource = 1;
$leadSource = 1; - it works when I assign value statically, but I want to get the value of "leadSource" and assign it to $leadSource
I want to get the leadSource and pass it to leadSourceSub query
Field 2:
$builder->addEventListener(FormEvents::PRE_SET_DATA, function (DataEvent $event) {
$form = $event->getForm();
$entity = $event->getData();
$leadSource = $entity->getLeadSourceID();
$form->add('leadSourceSub', 'C2Educate\ToolsBundle\Entity\Students', array(
'label' => ' Source Detail ',
'required' => true,
'class' => 'C2EducateToolsBundle:LeadSourceSubs',
'query_builder' => function($repo) use ($leadSource) {
return $repo->createQueryBuilder('p')
->where('p.lead_source_id =:leadSource')
->setParameter('leadSource', $leadSource)
->orderBy('p.sort_order', 'ASC');
},
'property' => 'name',
'empty_value' => 'Select'
));
});

Answer 1

You cannot get form data from $builder, because... it's a form builder, not a form. It doesn't contain any data yet.
To make this work you need to make use of FormEvents. In this case, you probably will need FormEvents::PRE_SET_DATA event listener.
$builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) {
$form = $event->getForm();
// in your case it's C2EducateToolsBundle:LeadSourceSubs
$entity = $event->getData();
$leadSource = $entity->getLeadSource();
// adding this field again will override it.
$form->add('leadSourceSub', 'entity', array(
'label' => ' Source Detail ',
'required' => true,
'class' => 'C2EducateToolsBundle:LeadSourceSubs',
'query_builder' => function($repo) use ($leadSource) {
return $repo->createQueryBuilder('p')
->where('p.lead_source_id =:leadSource')
->setParameter('leadSource', $leadSource)
->orderBy('p.sort_order', 'ASC');
},
'property' => 'name',
'empty_value' => 'Select'
));
}
});
Please note that this code is not tested and may need some validation like to check if $entity is what you expect it to be in any case.