protected function parseColumnValue($column, $row)
    {
        ob_start();
        $column->renderDataCell($row);
        $value = ob_get_clean();

        if ($column instanceof CDataColumn && array_key_exists($column->name, $this->extendedSummary['columns'])) {
            // lets get the configuration
            $config = $this->extendedSummary['columns'][$column->name];
            // add the required column object in
            $config['column'] = $column;
            // build the summary operation object
            $op = $this->getSummaryOperationInstance($column->name, $config);
            // process the value
            $op->processValue($value);
        }
        return $value;
    }