ASP.NET 在下载文件时对其重命名的思路及实现方法

string path = Server.MapPath("aa\ahaakladahsasdas_bb.zip");  
            string newfileName = "";  
            if (File.Exists(path))  
            {  
                FileInfo fi = new FileInfo(path);  
                Response.Clear();//Clear 方法删除缓冲区中的所有 HTML 输出。但 Clear 方法只删除响应正文  
                //而不删除响应标题。可以用该方法处理错误情况。  
                Response.ClearHeaders();  
                Response.Buffer = false;//这句话的意思就是指明输出页面是否被缓冲，当属性值为True时，  
                //服务器将不会向客户端发送任何信息，直到所有程序执行完或者遇到   
                //Response.Flush或Response.End语句，才会释放缓冲区的信息。  
                string filename = Path.GetFileName(path);  
                newfileName = newfileName + filename.Substring(filename.LastIndexOf("."));  
                Response.Clear();  
                Response.ClearHeaders();  
                Response.Buffer = false;  

                newfileName = HttpUtility.UrlEncode(newfileName);// 这一步弹出下载保存的对话框，出现文件名乱码，但变量中的文件名是正常的。    
                Response.AppendHeader("Content-Disposition", "attachment;filename=" + newfileName);//为用户保存文件是显示的名称  
                //告诉客户端这个响应内容的类型为attachment 你是通过Response.AppendHeader("content-type", "attachment"); 申明的。  

                Response.AppendHeader("Content-Length", fi.Length.ToString());  
                Response.ContentType = "application/octet-stream";  
                Response.WriteFile(newfileName);//用response来返回文件的路径    
                Response.Flush();//清空response    
                Response.End();  
                //Response.End(); 如果抛异常的话可使用  
                //HttpContext.Current.ApplicationInstance.CompleteRequest();  
            }  
            else  
            {  
                Response.Write("");  
            }