public function getRawData($columnNames = null, $namedIndexes = true)
    {
        if ($columnNames === null) {
            foreach ($this->getColumns() as $column) {
                $columnNames[] = $column->getId();
            }
        }

        $columnNames = (array) $columnNames;
        $result = [];
        foreach ($this->rows as $row) {
            $resultRow = [];
            foreach ($columnNames as $columnName) {
                if ($namedIndexes) {
                    $resultRow[$columnName] = $row->getField($columnName);
                } else {
                    $resultRow[] = $row->getField($columnName);
                }
            }

            $result[] = $resultRow;
        }

        return $result;
    }