symfony flashBag message not working

Question

I'm building a symfony 3 project and I'm trying to show a flashbag message in twig template after submit the form to notice the user that the form has been submitted successfully but it's not working for me ! here is the controller :

<?php
namespace EvalBundle\Controller;

use EvalBundle\Entity\SessionEvaluation;
use EvalBundle\Form\SessionEvaluationType;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Method;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;

class EvaluationController extends Controller
{
    /**
     * @Route("/evaluation", name="evaluation_session")
     * @Method({"GET", "POST"})
     */
    public function indexAction(Request $request)
    {
        $sessioneval = new SessionEvaluation();
        $form = $this->createForm(SessionEvaluationType::class, $sessioneval);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()){

            $em = $this->getDoctrine()->getManager();
            $em->persist($sessioneval);
            $em->flush();
            $this->get('session')->getFlashBag()->add('notice', 'la session est lancée avec succes');
            unset($entity);

        }
        return $this->render('@Eval/Default/Evaluation/newEvaluationSession.html.twig',array(
            'form' => $form->createView()
        ));


    }
}

and here is the twig template :

{% extends ':default:superAdminBase.html.twig' %}

{% block menu %}
    {% include(':default:menu.html.twig') %}
{% endblock %}

{% block header %}
{% endblock %}

{% block body %}
    <div class="row">
        <div class="col-lg-12 col-md-12 col-sm-12">
            <h1 class="page-header">
                Lancer une nouvelle session d'évaluation
            </h1>
        </div>
    </div>
    {% set flashbag_notices = app.session.flashBag('notice') %}
    {% if flashbag_notices is not empty %}
        <div class="row">
            <div class="col-lg-6">
                <ul>
                    {% for notice in  flashbag_notices %}
                        {{ dump(flashbag_notices) }}
                        <li>{{ notice }}</li>
                    {% endfor %}
                </ul>
            </div>
        </div>
    {% endif %}

    <div class="row">
        <div class="col-md-12">
            <div class="panel panel-default">
                <div class="panel-heading">
                    Session d'évaluation des Compétences
                </div>
                <div class="panel-body">
                    <div class="row">
                        <div class="container">
                            <div class="col-lg-12 ">
                                {{ form_start(form) }}
                                {{ form_widget(form) }}
                                {{ form_end(form) }}
                            </div>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>
{% endblock %}
{% block javascript %}

{% endblock %}

I've followed the doc but I don't know it's not working on my side.

some help please ! thanks

Answer 1

Try changing this line:

$this->get('session')->getFlashBag()->add('notice', 'la session est lancée avec succes');

TO:

$request->getSession()->getFlashBag()->add('notice', 'la session est lancée avec succes');

Alternately you can do:

$this->addFlash(
    'notice',
    'la session est lancée avec succes'
);

And in Twig get like so:

{% set flashbag_notices = app.session.flashBag('notice') %}

If you happen to be running Symfony 3.3, you can instead use this:

{% set flashbag_notices = app.flashes('notice') %}

As per the new changes:

https://symfony.com/blog/new-in-symfony-3-3-improved-flash-messages