1.先去官網：http://npoi.codeplex.com/下載需要引入dll 然後在網站中添加引用。
2.Asp.Net mvc導出方法
/// <summary>
        /// 導出Excel
        /// </summary>
        /// <returns></returns>
        public FileResult Excel()
        {
            var alist = WishWallServices.QueryWhere(c => c.status == 1).OrderByDescending(c=>c.WishThumbup.Where(q=>q.status==1
 
).Count()).ToList();
            //創建Excel文件的對象
            NPOI.HSSF.UserModel.HSSFWorkbook book = new NPOI.HSSF.UserModel.HSSFWorkbook();
            //添加一個sheet
            NPOI.SS.UserModel.ISheet sheet1 = book.CreateSheet("心願墻");
            //給sheet添加第一行的頭部標題
            NPOI.SS.UserModel.IRow row1 = sheet1.CreateRow(0
 
);
            row1.CreateCell(0).SetCellValue("微信號");
            row1.CreateCell(1).SetCellValue("姓名");
            row1.CreateCell(2).SetCellValue("心願標題");
            row1.CreateCell(3).SetCellValue("心願內容");
            row1.CreateCell(4).SetCellValue("點贊數");
            row1.CreateCell(5).SetCellValue("
 
聯系方式");
            row1.CreateCell(6).SetCellValue("聯系地址");
            //....N行

            //將數據逐步寫入sheet1各個行
            for (int i = 0; i < alist.Count; i++)
            {
                NPOI.SS.UserModel.IRow rowtemp = sheet1.CreateRow(i + 1);
                rowtemp.CreateCell(0).SetCellValue(alist[i].WeiXinInfo.WeiXinName);
                rowtemp.CreateCell(1).SetCellValue(alist[i].name);
                rowtemp.CreateCell(2).SetCellValue(alist[i].title);
                rowtemp.CreateCell(3).SetCellValue(alist[i].content);
                rowtemp.CreateCell(4).SetCellValue(alist[i].WishThumbup.Where(q=>q.status==1).Count());
                rowtemp.CreateCell(5).SetCellValue(alist[i].phone);
                //....N行
            }
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            book.Write(ms);
            ms.Seek(0, SeekOrigin.Begin);
            return File(ms, "application/vnd.ms-excel", "心願墻.xls");
        }

使用NPOI 做Excel導出