title: Symfony: how to get values from parameters.yml in an AbstractType
body: <p>I'm trying to get values form an array which I declared in parameters.yml</p>
  
  <pre><code># parameters.yml
  parameters:
      ...
      objects: {object1: 1, object2: 2, object3: 3}
  </code></pre>
  
  <p>but once I try to get "objects" from that file using this code </p>
  
  <pre><code>$builder-&gt;add('list', ChoiceType::class, array ('objects' =&gt; $this-&gt;container-&gt;getParameter('categories') ));
  </code></pre>
  
  <p>I get the following error </p>
  
  <pre><code>Notice: Undefined property: Project\Bundle\Form\EntityType::$container
  </code></pre>
  
  <p>Any suggestions?</p>