function add_data($row, $classname = '') {
        if (!$this->setup) {
            return false;
        }
        if (!$this->started_output) {
            $this->start_output();
        }
        if ($this->exportclass!==null) {
            if ($row === null) {
                $this->exportclass->add_seperator();
            } else {
                $this->exportclass->add_data($row);
            }
        } else {
            $this->print_row($row, $classname);
        }
        return true;
    }