Symfony 1.4 I have trouble getting a value of a hidden field

Question

When I create a new record, in the action processForm I need to get the value of a hidden field called idmensajes. This field is a hidden field, auto-incremental and prymary key. But when I use getValue ('idmensajes') the result is empty. Why? How I can get the value of idmensajes in processForm?

Here the code of processForm:

 protected function processForm(sfWebRequest $request, sfForm $form)
  {
    $form->bind($request->getParameter($form->getName()), $request->getFiles($form->getName()));
    if ($form->isValid())
    {      
          $form_vals = $this->form->getValue('idmensajes');

      $mensajes = $form->save();
      $this->redirect('mensajes/index');

In order to view captured values​​, corresponding to two fields, I added:

$form_vals1 = $this->form->getValue('idmensajes');
  $form_vals2= $this->form->getValue('cuerpo');


 $this->getUser()->setFlash("val1", $form_vals1);
$this->getUser()->setFlash("val2", $form_vals2);  

In the view, indexSuccess.php, I add the code:

<?php echo 'El valor del Id es:'. $sf_user->getFlash('val1'); ?>
<br>
<?php echo 'El valor de Cuerpo es: '. $sf_user->getFlash('val2'); ?>

Then, I view the value of val2 but the value val1 is empty.

Here the complete code, with Flash add:

protected function processForm(sfWebRequest $request, sfForm $form)
  {
    $form->bind($request->getParameter($form->getName()), $request->getFiles($form->getName()));
    if ($form->isValid())
    {      

      $mensajes = $form->save();

       $form_vals1 = $this->form->getValue('idmensajes');
      $form_vals2= $this->form->getValue('cuerpo');

         $this->getUser()->setFlash("val1", $form_vals1);
        $this->getUser()->setFlash("val2", $form_vals2);  

      $this->redirect('mensajes/index');

Answer 1

First check if idmensajes exist, and if you can get another field from your form.

Try this:

$this->form['idmensajes']->getValue(),

upd

Try:

 $mensajes = $form->save();
 $idmensajes = $mensajes->getIdmenSajec()// or other getter