设置Excel模板某列为DropDownList形式，用户不用输入，采取选择的方式避免输入的信息不符合要求

   using (FileStream file = new FileStream(Path.Combine(HttpContext.Current.Server.MapPath(HttpContext.Current.Request.ApplicationPath), filepath + filename + ".xls"), FileMode.Open, FileAccess.Read))   using (FileStream file = new FileStream(Path