public function getDropDownField($emptystring = null, $values = null)
    {
        $values = ($values) ? $values : $this->Values()->sort(['Sort' => 'ASC', 'Value' => 'ASC']);

        if ($values->exists()) {
            $field = DropdownField::create(
                'ProductAttributes[' . $this->ID . ']',
                $this->Name,
                $values->map('ID', 'Value')
            );

            if ($emptystring) {
                $field->setEmptyString($emptystring);
            }

            return $field;
        }

        return null;
    }