C#将数据写入到给定的模板中

//  调用
       ToExcel_ByTemplate(model.MainList, Server.MapPath("~/template/" + "模板表" + ".xlsx"), Server.MapPath("~/download/" + "目标表" + ".xlsx"));
      //List<T> data需要导出的数据列表 fileTemplate模板地址 feedbackFileName将要导出的地址
      public static void ToExcel_ByTemplate(List<T> data, string fileTemplate, string feedbackFileName)
    {
        int j = 0;
        System.IO.FileStream file = new System.IO.FileStream(fileTemplate, FileMode.Open, FileAccess.Read);

        XSSFWorkbook hssfworkbook = new XSSFWorkbook(file);
        XSSFSheet ws = hssfworkbook.GetSheet("Sheet1") as XSSFSheet;//将数据导入到给定的sheet中
        if (data != null && data.Count>0)
        {
            for (int i = 0; i < data.Count; i++)
            {
                j++;
                IRow row = ws.CreateRow(j);
                //根据模板填充数据
                row.CreateCell(0).SetCellValue(data[i].data1);
                row.CreateCell(1).SetCellValue(data[i].data2);
                row.CreateCell(2).SetCellValue(data[i].data3);                     
            }
        }

        using (FileStream filess = File.OpenWrite(feedbackFileName))
        {
            hssfworkbook.Write(filess);
        }
    }
 #region 下载文件
    /// <summary>
    /// 下载文件
    /// </summary>
    /// <param name="filepath">现在的文件相对路径</param>
    /// <param name="newfilename">另存为文件的路径</param>
    public void DownloadFile(string filepath, string newfilename)
    {
        System.IO.FileInfo filet = new System.IO.FileInfo(Server.MapPath(filepath));
        Response.Clear();
        Response.Buffer = true;
        Response.Charset = "UTF-8";
        Response.ContentEncoding = System.Text.Encoding.UTF8;
        // 添加头信息，为"文件下载/另存为"对话框指定默认文件名   
        //string newfilename1 = HttpUtility.UrlEncode(Encoding.UTF8.GetBytes(newfilename));
        //Response.AddHeader("Content-Disposition", "attachment; filename=" + newfilename1);
        Response.AddHeader("Content-Disposition", "attachment; filename=" + Server.UrlEncode(newfilename));
        // 添加头信息，指定文件大小，让浏览器能够显示下载进度   
        Response.AddHeader("Content-Length", filet.Length.ToString());

        // 指定返回的是一个不能被客户端读取的流，必须被下载   
        Response.ContentType = "application/ms-excel";

        // 把文件流发送到客户端   
        Response.WriteFile(filet.FullName);
        // 停止页面的执行   
        //Response.End();
        HttpContext.Current.ApplicationInstance.CompleteRequest(); 
    }
    #endregion