c#高效率导出多维表头excel的实例代码

[dllimport("user32.dll", charset = charset.auto)]
        public static extern int getwindowthreadprocessid(intptr hwnd, out int id);
        private void exporttoexcel(string fielname)
        {
            //实例化一个excel.application对象   
            microsoft.office.interop.excel.application excel = new microsoft.office.interop.excel.application();

            try
            {
                if (dgv_result.datasource == null)
                    return;
                if (dgv_result.rows.count == 0)
                    return;

                //新增加一个工作簿，workbook是直接保存，不会弹出保存对话框，加上application会弹出保存对话框，值为false会报错   
                microsoft.office.interop.excel.workbook xlbook = excel.workbooks.add(true);

                //1.添加表头
                excel.cells[1, 1] = tyclass;
                for (int i = 0; i < dgv_result.columns.count; i++)
                {

                    excel.cells[2, i + 1] = dgv_result.columns[i].name;
                }

                #region 2.实现excel多维表头 采用合并单元格的方式
                microsoft.office.interop.excel.worksheet sheet = (microsoft.office.interop.excel.worksheet)xlbook.activesheet;
                microsoft.office.interop.excel.range excelrange = sheet.get_range(sheet.cells[1, 1], sheet.cells[1, 2]);
                microsoft.office.interop.excel.range excelrange1 = sheet.get_range(sheet.cells[1, 3], sheet.cells[1, 4]);
                microsoft.office.interop.excel.range excelrange2 = sheet.get_range(sheet.cells[1,5], sheet.cells[1, 6]);
                microsoft.office.interop.excel.range excelrange3 = sheet.get_range(sheet.cells[1,7], sheet.cells[1, 8]);
                microsoft.office.interop.excel.range excelrange4 = sheet.get_range(sheet.cells[1, 2], sheet.cells[1, 3]);
                microsoft.office.interop.excel.range excelrange5 = sheet.get_range(sheet.cells[1, 6], sheet.cells[1, 7]);
                microsoft.office.interop.excel.range excelrange6 = sheet.get_range(sheet.cells[1, 4], sheet.cells[1,5]);
                excelrange.merge(excelrange.mergecells);
                excelrange1.merge(excelrange1.mergecells);
                excelrange4.merge(excelrange4.mergecells);
                excelrange2.merge(excelrange2.mergecells);
                excelrange3.merge(excelrange3.mergecells);
                excelrange5.merge(excelrange5.mergecells);
                excelrange6.merge(excelrange6.mergecells);
                microsoft.office.interop.excel.range columnrange = sheet.get_range("a1", "h2");   //得到  range 范围  a-h 表示1-8列，1-2表示跨几行
                 columnrange.horizontalalignment = microsoft.office.interop.excel.xlhalign.xlhaligncenter;
                 columnrange.font.size = 10;
                 columnrange.font.bold = true;

                #endregion

               
                #region 3.添加行数据，直接给range赋值可提高效率

                 microsoft.office.interop.excel.range range = sheet.get_range("a3", "h" + (dgv_result.rows.count + 2).tostring());   //得到  range 范围
                string[,] arydata = new string[dgv_result.rows.count-1, dgv_result.columns.count];
                for (int i = 0; i < dgv_result.rows.count - 1; i++)
                {
                    for (int j = 0; j < dgv_result.columns.count; j++)
                    {

                        arydata[i,j] = dgv_result.rows[i].cells[j].value.tostring();
                    }
                }
                range.value2 = arydata;
                range.horizontalalignment = microsoft.office.interop.excel.xlhalign.xlhaligncenter;
                #endregion

                sheet.cells.columns.autofit();//设置excel表格的  列宽
                excel.sheetsinnewworkbook = 1;//设置excel单元格对齐方式
                excel.displayalerts = false; //设置禁止弹出保存和覆盖的询问提示框   
                excel.alertbeforeoverwriting = false;
                //保存excel文件   
                xlbook.saveas(fielname, microsoft.office.interop.excel.xlfileformat.xlworkbooknormal, type.missing, type.missing, type.missing, type.missing, microsoft.office.interop.excel.xlsaveasaccessmode.xlexclusive, type.missing, type.missing, type.missing, type.missing, type.missing);
                messagebox.show("导出成功！", "提示");
            }
            catch (exception ex)
            {
                messagebox.show(ex.message, "错误提示");
            }
            finally
            {
                intptr pt = new intptr(excel.hwnd);
                int k = 0;
                getwindowthreadprocessid(pt, out k);
                system.diagnostics.process p = system.diagnostics.process.getprocessbyid(k);
                p.kill();

            }

        }