php - Can't process the form in the controller - Symfony -

i started using symfony , i'm trying make simple prime number checker. controller doesn't seem work though, because though see form, after input number nothing happens ( text should appear saying if number prime or not )

<?php  namespace appbundle\controller;  use appbundle\entity\calculator; use sensio\bundle\frameworkextrabundle\configuration\route; use symfony\bundle\frameworkbundle\controller\controller; use symfony\component\httpfoundation\request; class todocontroller extends controller {     /**      * @route("/prime")      */     public function listaction()     {           return $this->render('todo/index.html.twig');     }     public function doitaction(request $request)     {           $data = $form->getdata();         return calculator::checknumber($data);     } } 

your code snippet missing i'm not sure if removed on purpose or it's empty.

please form examples documentation http://symfony.com/doc/current/forms.html

main part missing is

if ($form->handlerequest($request)->isvalid()) {     $data = $form->getdata();      // something, render template etc }