public function applyTDParams($field, &$row_template = null)
    {
        // data row template by default
        if (!$row_template) {
            $row_template = &$this->row_t;
        }

        // setting cell parameters (tdparam)
        $tdparam = $this->tdparam[$this->getCurrentIndex()][$field];
        $tdparam_str = '';
        if (is_array($tdparam)) {
            if (is_array($tdparam['style'])) {
                $tdparam_str .= 'style="';
                foreach ($tdparam['style'] as $key => $value) {
                    $tdparam_str .= $key.':'.$value.';';
                }
                $tdparam_str .= '" ';
                unset($tdparam['style']);
            }

            //walking and combining string
            foreach ($tdparam as $id => $value) {
                $tdparam_str .= $id.'="'.$value.'" ';
            }

            // set TD param to appropriate row template
            $row_template->set("tdparam_$field", trim($tdparam_str));
        }
    }