public void ExportExcel()
 {
     try
     {
         if (!string.IsNullOrEmpty(Request.Params["group_id"]))
         {
             _emailGroupMgr = new EmailGroupMgr(mySqlConnectionString);
             DataTable _dt = _emailGroupMgr.Export(Convert.ToInt32(Request.Params["group_id"]));
             DataTable _newDt = new DataTable();
             _newDt.Columns.Add("群組代碼", typeof(string));
             _newDt.Columns.Add("電子信箱地址", typeof(string));
             _newDt.Columns.Add("收件人名稱", typeof(string));
             for (int i = 0; i < _dt.Rows.Count; i++)
             {
                 DataRow newRow = _newDt.NewRow();
                 newRow[0] = _dt.Rows[i]["group_id"];
                 newRow[1] = _dt.Rows[i]["email_address"];
                 newRow[2] = _dt.Rows[i]["name"];
                 _newDt.Rows.Add(newRow);
             }
             string fileName = "信箱名單管理匯出" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".xls";
             MemoryStream ms = ExcelHelperXhf.ExportDT(_newDt, "");
             Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName);
             Response.BinaryWrite(ms.ToArray());
         }
     }
     catch (Exception ex)
     {
         Log4NetCustom.LogMessage logMessage = new Log4NetCustom.LogMessage();
         logMessage.Content = string.Format("TargetSite:{0},Source:{1},Message:{2}", ex.TargetSite.Name, ex.Source, ex.Message);
         logMessage.MethodName = System.Reflection.MethodBase.GetCurrentMethod().Name;
         log.Error(logMessage);
     }
 }