ExcelExportV2

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using System.IO;
using System.Web.Mvc;

namespace ExcelExportMVCLab.Controllers
{
    public class ExcelExportV2Controller : Controller
    {
        /// <summary>
        /// 副檔名為xls(Excel97-2003格式)
        /// </summary>
        public void ExportXls()
        {
            string fileName = "ExportData.xls";

            IWorkbook workbook = new HSSFWorkbook();
            ISheet sheet = workbook.CreateSheet("Sheet1");

            ExportExcel(workbook, fileName);
        }

        /// <summary>
        /// 副檔名為xlsx(Excel2007以上格式)
        /// </summary>
        public void ExportXlsx()
        {
            string fileName = "ExportData.xlsx";

            IWorkbook workbook = new XSSFWorkbook();
            ISheet sheet = workbook.CreateSheet("Sheet1");

            ExportExcel(workbook, fileName);
        }

        private void ExportExcel(IWorkbook workbook, string fileName)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                workbook.Write(ms);

                Response.Clear();
                if(fileName.ToLower().EndsWith(".xls"))
                    Response.ContentType = "application/vnd.ms-excel";
                else if (fileName.ToLower().EndsWith(".xlsx"))
                    Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                Response.AddHeader("content-disposition", "attachment; filename=" + fileName);
                Response.BinaryWrite(ms.ToArray());
                Response.Flush();
                Response.End();
            }
        }
    }
}