title: Retrieve a value inside a field using a custom twig / Select a column by it's block name / Sonata
body: <p>I'll try to be clear as possible, as my question may not be simple.</p>
  
  <p>I have a Sonata GridPanel, modelled (simplified) like this:</p>
  
  <p>~~~~~~~~~~~~~~~<br>
  Name   |   Type   |  Blob</p>
  
  <p>~~~~~~~~~~~~~~~<br>
  Boby   | Aaaa | Bbbb<br>
  John   | Cccc | Xxxx<br><br></p>
  
  <p>Let assume the column <b>Blob</b> is a custom column I made which you can click on.<br>
  It is controlled by a custom twig.</p>
  
  <p>My custom twig is like this</p>
  
  <pre><code>{% extends stuff %}
  {% block field%}
  &lt;div class="opener"&gt;
      &lt;img 
      src="{{ asset('bundles/bobby/images/map_magnify.png') }}" 
      width="30" 
      height="30"
      style="cursor:pointer;" 
      onclick="createPopUp('{{ admin.id(object) }}');"  
      &gt;
  &lt;/div&gt;
  {% endblock %}
  </code></pre>
  
  <p>As you can see, I pass the <b>{{ admin.id(object) }}</b> as a parameters of the function, so the function in my JS file will be aware of the value returned by the parameters.<br></p>
  
  <p>For example, according to my grid there and assuming the ID of my object is the column Name, if I click on <b>Bbbb</b>, the <b>{{ admin.id(object) }}</b> will return <b>Boby</b> as a value.</p>
  
  <p>This is working.</p>
  
  <p>Now, I want to do quite the same thing, but not returns the ID of a whole object, but a specific value of an object.<br>
  Still according to my example, if I click on <b>Bbbb</b>, I would like to retrieve the value contained in the column <b>Type</b> for this object. The value should be then <b>Aaaa</b>.</p>
  
  <p>But I don't know how to do this.
  I tried to pass this <b>{{ block('field') }}</b>, but it does not target a specific column.<br> How can I select the block by it's name.</p>
  
  <p>I'm not familiar enough with twig and I'm quite lost looking inside all the Sonata's twig files.<br>
  How could I do this ?</p>
  
  <p>You'll have to know to that in my case, the value I want to retrieve is "controlled" by a Sonata's Twig, and not by my custom twig.</p>