public class UserInfo

    {

        public string Name { get; set; }

        public string Id { get; set; }

        public string Phone { get; set; }

    }

  /// <summary>

        /// 生成excel文件到内存中

        /// </summary>

        /// <returns></returns>

        public void CreateExcel()

        {

            MemoryStream ms = new MemoryStream();

            List<UserInfo> listUser = new List<UserInfo>()

           {

               new UserInfo { Name="1", Id="1", Phone="1r" },

               new UserInfo { Name="2", Id="2", Phone="2r" },

               new UserInfo { Name="3", Id="3", Phone="3r" },

               new UserInfo { Name="4", Id="4", Phone="4r" },

               new UserInfo { Name="5", Id="5", Phone="5r" },

           };

            //创建工作簿对象

            var workbook = new HSSFWorkbook();

            #region DataTable数据

            //创建工作表

            ISheet sheet = workbook.CreateSheet("一个sheet");

            IRow row0 = sheet.CreateRow(0);

            row0.CreateCell(0).SetCellValue("用户Id");

            row0.CreateCell(1).SetCellValue("用户名称");

            row0.CreateCell(2).SetCellValue("用户备注信息");

            var dtSource = GetDataTable();

            for (int i = 0; i < dtSource.Rows.Count; i++)

            {

                row0 = sheet.CreateRow(i + 1);

                for (int j = 0; j < dtSource.Columns.Count; j++)

                {

                    row0.CreateCell(j).SetCellValue(dtSource.Rows[i][j].ToString());

                }

            }

            #endregion

            #region list数据

            ISheet sheet2 = workbook.CreateSheet("另一个sheet");

            IRow row2 = sheet2.CreateRow(0);

            row2.CreateCell(0).SetCellValue("用户Id2");

            row2.CreateCell(1).SetCellValue("用户名称2");

            row2.CreateCell(2).SetCellValue("用户备注信息2");

            for (int r = 1; r < listUser.Count; r++)

            {

                //创建行row

                IRow row = sheet2.CreateRow(r);

                row.CreateCell(0).SetCellValue(listUser[r].Id);

                row.CreateCell(1).SetCellValue(listUser[r].Name);

                row.CreateCell(2).SetCellValue(listUser[r].Phone);

            }

            #endregion

            workbook.Write(ms);

            ms.Flush();

            ms.Position = 0;

            var fileName = "测试Excel" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".xlsx";//xls

            DownloadExcel(ms, fileName);

        }

        /// <summary>

        /// 生成http流下载文件

        /// </summary>

        /// <param name="ms"></param>

        /// <param name="fileName"></param>

        private static void DownloadExcel(MemoryStream ms, string fileName)

        {

            #region 处理IE、火狐等浏览器文件名乱码

            if (System.Web.HttpContext.Current.Request.ServerVariables["http_user_agent"].IndexOf("Firefox", StringComparison.Ordinal) != -1)

            {

                fileName = "=?UTF-8?B?" + Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(fileName)) + "?=";

            }

            else

            {

                fileName = System.Web.HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8);

                fileName = fileName.Replace("+", "%20");

            }

            #endregion

            System.Web.HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;fileName=" + fileName);

            System.Web.HttpContext.Current.Response.AddHeader("Content-Length", ms.Length.ToString());

            System.Web.HttpContext.Current.Response.AddHeader("Content-Transfer-Encoding", "binary");

            System.Web.HttpContext.Current.Response.ContentType = "application/octet-stream;charset=utf-8";

            System.Web.HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.UTF8;

            System.Web.HttpContext.Current.Response.BinaryWrite(ms.ToArray());

        }

        /// <summary>

        /// 模拟DataTable

        /// </summary>

        /// <returns></returns>

        public DataTable GetDataTable()

        {

            DataTable tblDatas = new DataTable("Datas");

            DataColumn dc = null;

            dc = tblDatas.Columns.Add("Name", Type.GetType("System.String"));

            dc = tblDatas.Columns.Add("Id", Type.GetType("System.String"));

            dc = tblDatas.Columns.Add("Phone", Type.GetType("System.String"));

            DataRow newRow;

            newRow = tblDatas.NewRow();

            newRow["Name"] = "大话西游";

            newRow["Id"] = "2.0";

            newRow["Phone"] = "我很喜欢";

            tblDatas.Rows.Add(newRow);

            newRow = tblDatas.NewRow();

            newRow["Name"] = "梦幻西游";

            newRow["Id"] = "3.0";

            newRow["Phone"] = "比大话更幼稚";

            tblDatas.Rows.Add(newRow);

            return tblDatas;

        }