Symfony2 Form Events without entity - forms

Question

I want to make a search form that acts independently from the entity, so there's no entity, and a choice field is dynamically loaded from other using FormEvents but no matter what always getting $formE->getData() NULL
this is my code of the controller
public function indexAction(Request $request)
{
$form = $this->createFormBuilder()
->add('Numero', TextType::class,array('required' => false,))
->add('FechaIngresoRango',TextType::class,array('required' => false,))
->add('Criterio', ChoiceType::class, array(
'choices' => array(
'' => '-Seleccione Opcion-',
'form_Numero' => 'NUMERO',
'form_Sector' => 'AREA',
'inputGroupsTema' => 'TEMA',
'form_FechaIngresoRango' => 'FECHA INGRESO',
),'required' => true))
->add('Sector','entity', array(
'class' => 'AppBundle\Entity\Sector',
'property' => 'nombre',
'required' => false
))
->add('Tema','entity', array(
'class' => 'AppBundle\Entity\TipoTemaExpediente',
'property' => 'tipoTemaExpediente',
'required' => false
))->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) {
$formE = $event->getForm();
$data = $event->getData();
var_dump($data);
{
$em = $this->getDoctrine()->getManager();
$tiposSubTema = $em->getRepository('AppBundle:TipoSubTemaExpediente')->findAll();
//$tipoTema = $data->getTipoTemaExpediente();
$formE->add('tipoSubTemaExpediente',EntityType::class,array(
'class' => 'AppBundle:TipoSubTemaExpediente',
'property' => 'subTemaExpediente',
'choices' => $tiposSubTema,
));
}
//else
{
//$formE->add('tipoSubTemaExpediente',ChoiceType::class, array('attr' => array('disabled' => true),));
}
})
->getForm();
$form->handleRequest($request);
if ($form->isValid()) {
$data = $form->getData();
// switch ($data['Criterio']){
// case "form_Numero" :
// var_dump($data['Numero']);
// break;
// case "form_Sector" :
// var_dump($data['Sector']->getId());
// break;
// case "inputGroupsTema" :
// var_dump($data['Tema']->getTipoTemaExpediente());
// break;
// case "form_FechaIngresoRango" :
// var_dump($data['FechaIngresoRango']);
// break;
// }
}
the comments are from several test that I did, on post works flawlessly the problem is the event, I'm starting to think that if no entity is related on the form creation there's no way that this going to work, is that so?