public static MemoryStream ExportToExcel(DataSet ds,ExcelType excelType,string header)

        {

            IWorkbook workbook = null;

            if (excelType==ExcelType.Office2003)

            {

                workbook = new HSSFWorkbook();//2003

            }

            else

            {

                workbook = new XSSFWorkbook();//2007

            }



            #region 开始循环DS中的Table,DS中的每个表创建一个Sheet

            for (int p = 0; p < ds.Tables.Count; p++)

            {

                #region 创建一个sheet

                ISheet sheet = workbook.CreateSheet("sheet" + (p + 1));

                //设置大标题行   

                int rowCount = 0;





                //设置全局列宽和行高   

                sheet.DefaultColumnWidth = 14; //全局列宽   

                sheet.DefaultRowHeightInPoints = 15; //全局行高   

                //设置标题行数据   

                int a = 0;

                



                IRow row1 = sheet.CreateRow(rowCount); //创建报表表头标题列   

                //for (int k = 0; k < ds.Tables[p].Columns.Count; k++)

                //{ //将DataTable的列标题输出到Excel

                //    columnName = ds.Tables[p].Columns[k].ColumnName;

                //    row1.CreateCe