title: Render forms in sonata admin listview
body: <p>I my application i have a listview representing News-items. On each row end i want to add a plus-sign button and by clicking it, a little inline form should pop up in a bubble (via bootstrap dropdown). To render this form, my actually approach is to render this via the <code>render(controller(...))</code> mechanism in the field template.</p>
  
  <pre><code>{% extends 'SonataAdminBundle:CRUD:base_list_field.html.twig' %}
  
  {% block field %}
    {{ render(controller(...)) }}
  {% endblock %}
  </code></pre>
  
  <p>The render controller call renders a form according to the official symfony documentation ...</p>
  
  <p>The rendered form sends it data back to the commentAction in the same controller.</p>
  
  <p>In theory it works fine, but practical its slow as hell. My site runs in timeout after 60 seconds just because in the listview are default 64 items shown and each item calls this render controller function ...</p>
  
  <p>Is there a clean way to render a little extra form not by invoking a expensive render controller call? </p>
  
  <p>I think it could work with manipulating the listAction method in the controller (injecting here the extra form?) ... but this does not seem a clean solution.</p>
  
  <p>Any ideas? </p>
  
  <p>Thanks</p>
  
  <p>Edit:</p>
  
  <p>Ok, i think i found out, where the bottleneck is ... the example above was simplified. In reality i load a collection into the form for every row ... in the form you can choose, which author created the news. There are at least 500 Authors in that list ... so displaying these authors for a single new, everything is fine. But rendering the choose options 64 times is too much. Is there a way to make this faster? Some caching mechanism?</p>