后台模拟弹出上传匡

 FileInfo fi = new FileInfo(fileName);//excelFile为文件在服务器上的地址
                    HttpResponse contextResponse = HttpContext.Current.Response;
                    contextResponse.Clear();
                    contextResponse.Buffer = true;
                    contextResponse.Charset = "UTF8"; //设置了类型为中文防止乱码的出现
                    string downloadName = month.Replace("/", "年") + "月份客运设备设备设施维护管理表.xls";
                    string broswer = context.Request.UserAgent.ToLower();
                    if (broswer.IndexOf("msie") > -1
                        || broswer.IndexOf("edge") > -1
                        || broswer.IndexOf("like gecko") > -1)
                    {
                        downloadName = HttpUtility.UrlPathEncode(downloadName);
                    }
                    contextResponse.AppendHeader("Content-Disposition", String.Format("attachment;filename={0}", downloadName)); //定义输出文件和文件名
                    contextResponse.AppendHeader("Content-Length", fi.Length.ToString());
                    contextResponse.ContentEncoding = Encoding.UTF8;
                    contextResponse.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。
                    //HttpContext.Current.Server.UrlEncode()
                   
                    contextResponse.WriteFile(fi.FullName);
                    contextResponse.Flush();
                    context.ApplicationInstance.CompleteRequest();