kartik\export\ExportMenu::generateHeader PHP Метод

    public function generateHeader()
    {
        $columns = $this->getVisibleColumns();
        if (count($columns) == 0) {
            return;
        }
        $sheet = $this->_objPHPExcelSheet;
        $style = ArrayHelper::getValue($this->styleOptions, $this->_exportType, []);
        $colFirst = self::columnName(1);
        $this->_endCol = 0;
        foreach ($this->getVisibleColumns() as $column) {
            $this->_endCol++;
            /**
             * @var DataColumn $column
             */
            $head = $column instanceof DataColumn ? $this->getColumnHeader($column) : $column->header;
            $id = self::columnName($this->_endCol) . $this->_beginRow;
            $cell = $sheet->setCellValue($id, $head, true);
            // Apply formatting to header cell
            $sheet->getStyle($id)->applyFromArray($style);
            $this->raiseEvent('onRenderHeaderCell', [$cell, $head, $this]);
        }
        for ($i = $this->_headerBeginRow; $i < $this->_beginRow; $i++) {
            $sheet->mergeCells($colFirst . $i . ":" . self::columnName($this->_endCol) . $i);
        }
        // Freeze the top row
        $sheet->freezePane($colFirst . ($this->_beginRow + 1));
    }