/// <summary>
        /// 下載匯入資料地圖模板
        /// </summary>
        /// <returns></returns>
        [HttpGet]
        public FileResult DownloadMapTemplate()
        {
            NpoiMemoryStream memory = new NpoiMemoryStream();
            IWorkbook workbook = new XSSFWorkbook();
            ISheet sheet=workbook.CreateSheet("匯入地圖資料模板");
            IRow row = sheet.CreateRow(0);
            row.CreateCell(0).SetCellValue("專案名稱");
            row.CreateCell(1).SetCellValue("地圖名稱");
            row.CreateCell(2).SetCellValue("地圖型別");
            row.CreateCell(3).SetCellValue("經緯度");
            ISheet sheet1 = workbook.GetSheetAt(0);//獲得第一個工作表  
            CellRangeAddressList regions = new CellRangeAddressList(1, 65535, 2, 2);//約束範圍：c2到c65535  
            XSSFDataValidationHelper helper = new XSSFDataValidationHelper((XSSFSheet)sheet1);//獲得一個數據驗證Helper  
            IDataValidation validation = helper.CreateValidation(helper.CreateExplicitListConstraint(new string[]{"專案","標段","橋樑","隧道"}), regions);//建立約束
            validation.CreateErrorBox("錯誤", "請按右側下拉箭頭選擇!");//不符合約束時的提示  
            validation.ShowErrorBox = true;//顯示上面提示 = True  
            sheet1.AddValidationData(validation);//新增進去  
            sheet1.ForceFormulaRecalculation = true;  


            memory.AllowClose = false;
            workbook.Write(memory);
            memory.Flush();
            memory.Position = 0;    // 指定記憶體流起始值
            
            return File(memory, "application/vnd.ms-excel","地圖模板下載.xlsx");
        }
 

注：此程式碼適用於XSSFWorkbook新版本