public function getDisplayField()
    {
        if (is_null($this->_displayField)) {
            $properties = array_keys($this->getDescriptor()->getColumns());
            foreach ($properties as $property) {
                $name = trim($property, '_');
                $pmk = $this->getDescriptor()->getEntity()->primaryKey;
                if ($name == $pmk) {
                    continue;
                }

                $annotations = $this->getDescriptor()->getInspector()
                    ->getPropertyAnnotations($property);

                if ($annotations->hasAnnotation('@display')) {
                    $this->_displayField = $name;
                    break;
                }
                $this->_displayField = $name;
            }
        }
        return $this->_displayField;

    }