isValid() method return false in symfony - symfony

Question

I am using symfony3 with window 7 AND using custom form rending. like that
{{ form_start(form,{ 'attr': {'class': 'form-horizontal','role':'form','id':'form'} }) }}
---- form field here
{{ form_widget(form._token) }}
{{ form_end(form, {'render_rest': false}) }}
/**
* #Route("entity/entity/{id}", name="entity_entity",defaults={"id" = 0})
*/
public function entityAction(Request $request,$id){
$action = false;
$arr_XYZ_data = array();
$arr_XYZ_prepare_data = array();
$form_title = 'Add New XYZ';
$obj_XYZ = new XYZ();
$form = $this->createForm(XYZType::class, $obj_XYZ);
if($id!=0){
$obj_repo = $this->getDoctrine()->getRepository('AppBundle:XYZ');
$arr_XYZ_data = $obj_repo->find($id);
if($arr_XYZ_data){
$action = true;
$form_title = 'Update XYZ';
$arr_XYZ_data = $obj_repo->findXYZById($id);
$arr_XYZ_prepare_data = $this->_prepareData($arr_XYZ_data);
}
}
$form->handleRequest($request);
if (($form->isSubmitted())&&($form->isValid())) {
$obj_XYZ->setXYZId($id);
$str_hiddenfield_result = $form->get('extraformfield')->getData();
$arr_hiddenfield_result = explode('&',$str_hiddenfield_result);
$obj_XYZ->setDef($obj_XYZ->getDef()->getDefId());
$obj_XYZ->setAbc($arr_hiddenfield_result[3]);
$obj_XYZ->setAuthor(1); //ldap session value
$em = $this->getDoctrine()->getManager();
$em->persist($obj_XYZ);
$em->flush();
$this->addFlash('success', 'Your record has been added successfully!');
return $this->redirectToRoute('XYZ_index', array(), 301);
}else{
$form->getErrors();
}
}
above code does not print any error but unable to submit. so please anyone can suggest me how can i fix the issue.
how to get all error in string with corresponding each form field.

Answer 1

Just calling the getter will not print anything, you need to do it by yourself using another (printing) function.
return new \Symfony\Component\HttpFoundation\Response($form->getErrors());
It will render a string containing all errors.
Depending on the context (traditional, ajax, ...), you can just re-render the form like so:
return $this->render('YourBundle:YourView.html.twig', [
'form' => $form->createView(),
]);
The errors should be properly displayed.