php - symfony2 form, collection of objects, issue updating existing object property -

the form consists of 1 question has several answers, answers can dynamically created each question. stuff works fine:

public function buildform(formbuilderinterface $builder, array $options) {     $builder         ->add('question','textarea')         ->add('answers', 'collection', array(             'type'=>new answertype(),             'allow_add'=>true,             'allow_delete'=>true,             'label' => false         ))     ; } 

here form code answertype:

    $builder         ->add('answer','text', array(             'attr'=>array(                 'class'=>'form-control'             ),             'label'=>false         ))         ->add('isgoodanswer', 'checkbox', array(             'label'=>'good?',             'required'=>false         ))     ; 

i using prototype template populate container via jquery.

adding new answer objects question object works fine. deleting answers not problem.

however, if go update existing property on 1 of collection form inputs not update existing object. persisting question object though update text of question itself. can delete , create new replace , having hard time figuring out why.

here snippet of code template form submitted:

    <ul id="answer-fields-list" data-prototype="{{ form_widget(form.answers.vars.prototype)|e }}">     {% answer in form.answers %}         <li>             <div class='col-md-12'>                                  {{ form_widget(answer) }}                                    <div>                     <a href='#' class='btn btn-sm btn-danger delete-this'><span class='glyphicon glyphicon-trash'></span></a>                 </div>             </div>                           </li>     {% endfor %}     </ul>                <a href="#" id="add-answer" class='btn btn-sm btn-success'><span class='glyphicon glyphicon-plus-sign'></span> add answer</a>            

edit, here full controller code update method:

    $question = $em->getrepository('checklistmainbundle:checklistquestion')->findonebyid($questionid);     if(!$question) throw new notfoundhttpexception('question not found');      $form = $this->createform(new questionanswertype(), $question);      $form->handlerequest($request);      if($request->getmethod()=='post' && $form->isvalid())     {         if($form->get('attachment')->getdata() != null) {             $question->uploadattachment();         }         $em->persist($question);         $em->flush();          $this->get('session')->getflashbag()->add('success', 'question modified successfully!');          return $this->redirect($this->generateurl('admin_checklists_view', array('id'=>$id)));     } 

after searching through google hours ran across duplicate question resembles mine.

how force doctrine update array type fields?

i adjusted setanswers method follows reflect answer:

 public function setanswers($answers)     {         if(!empty($answers) && $answers === $this->answers) {             reset($answers);             $answers[key($answers)] = clone current($answers);         }         $this->answers = $answers;         return $this;     } 

it saves existing answers fine, no more issues :)