fix form to jump to create a custom field

Controller/CustomFieldsGroupController.php

@@ -7,6 +7,7 @@ use Symfony\Bundle\FrameworkBundle\Controller\Controller;
 use Doctrine\ORM\Query;
 use Chill\CustomFieldsBundle\Entity\CustomFieldsGroup;
 use Chill\CustomFieldsBundle\Entity\CustomField;
+use Chill\CustomFieldsBundle\Form\DataTransformer\CustomFieldsGroupToIdTransformer;
 
 /**
  * CustomFieldsGroup controller.
@@ -210,17 +211,25 @@ class CustomFieldsGroupController extends Controller
             $fieldChoices[$key] = $customType->getName();
         }
         
-        return $this->createFormBuilder(new CustomField(), array(
+        $customfield = (new CustomField())
+              ->setCustomFieldsGroup($customFieldsGroup);
+        
+        $builder = $this->get('form.factory')
+              ->createNamedBuilder(null, 'form', $customfield, array(
                     'method' => 'GET',
-                    'action' => $this->generateUrl('customfield_new', 
+                    'action' => $this->generateUrl('customfield_new'),
-                            array('cfGroup' => $customFieldsGroup->getId())),
                     'csrf_protection' => false
                     ))
               ->add('type', 'choice', array(
                     'choices' => $fieldChoices
                    ))
-              ->add('submit', 'submit')
+              ->add('customFieldsGroup', 'hidden')
-              ->getForm();
+              ->add('submit', 'submit');
+        $builder->get('customFieldsGroup')
+              ->addViewTransformer(new CustomFieldsGroupToIdTransformer(
+                       $this->getDoctrine()->getManager()));
+        
+        return $builder->getForm();
     }
     
     /**

Form/DataTransformer/CustomFieldsGroupToIdTransformer.php

@@ -33,6 +33,14 @@ class CustomFieldsGroupToIdTransformer implements DataTransformerInterface
         if (null === $customFieldsGroup) {
             return "";
         }
+        
+        if (!$customFieldsGroup instanceof CustomFieldsGroup) {
+            throw new TransformationFailedException(sprintf('Transformation failed: '
+                  . 'the expected type of the transforme function is an '
+                  . 'object of type Chill\CustomFieldsBundle\Entity\CustomFieldsGroup, '
+                  . '%s given (value : %s)', gettype($customFieldsGroup), 
+                  $customFieldsGroup));
+        }
 
         return $customFieldsGroup->getId();
     }
@@ -49,6 +57,14 @@ class CustomFieldsGroupToIdTransformer implements DataTransformerInterface
         if (!$id) {
             return null;
         }
+        
+        if ($id instanceof CustomFieldsGroup) {
+            throw new TransformationFailedException(sprintf(
+                  'The transformation failed: the expected argument on '
+                  . 'reverseTransform is an object of type int,'
+                  . 'Chill\CustomFieldsBundle\Entity\CustomFieldsGroup, '
+                  . 'given', gettype($id)));
+        }
 
         $customFieldsGroup = $this->om
             ->getRepository('ChillCustomFieldsBundle:customFieldsGroup')->find($id)