title: CakePHP Join virtualField as displayField
body: <p>I'm trying to do one of two things, use a virtual field from a model as the display field in my join model, or use the virtual field as the display in a find('list') on my join model.</p>
  
  <p>Here's the current layout:</p>
  
  <p>MODELS</p>
  
  <pre><code>&lt;?php
  class Participant extends AppModel {
      public $hasMany = array('Registration');
  
      public $virtualFields = array(
          'full_name' =&gt; 'CONCAT(last_name, ", ", first_name)'
      );
  
      public $displayField = 'full_name';
  }
   -----
  class Contest extends AppModel {
      public $hasMany = array('Registration');
  
  }
  -----
  class Registration extends AppModel {
      public $belongsTo = array('Participant', 'Contest');
      public $hasMany = array('Assignment');
  
  }
  ?&gt;
  </code></pre>
  
  <p>Tables are as follows:</p>
  
  <pre><code>participants          contests       registrations
  ------------          ---------      --------------
  id                    id             id
  first_name            name           contest_id
  last_name                            participant_id
  </code></pre>
  
  <p>In my contests controller I'm trying to develop a list to be viewed as checkboxes in the view.  </p>
  
  <p>Here is the excerpt from my contests controller:</p>
  
  <pre><code>$this-&gt;loadModel('Registration');
          $this-&gt;set('registrations', $this-&gt;Registration-&gt;find(
                  'list',
                          array(
                              'conditions' =&gt; array('contest_id' =&gt; $contestId),
                              'recursive' =&gt; 1
                          )
              )
          );
  //$contestId is defined previously, and I have verified such.
  </code></pre>
  
  <p>This all actually runs fine as it is, and in the view will display a column of checkboxes with the registration_id as the label next to the checkbox.</p>
  
  <p>I would like to get a full_name as is defined in the Participant model to be the displayField of the Registration model.  I've been searching and can't quite seem to find a good way of doing that.  I hope I have been descriptive enough, and please let me know if you have any questions and I'll try to explain better.  Thank you.</p>
  
  <p>edit:  I'm using CakePHP 2.4.</p>