使用asp下的adodb.stream 下载文件而不是打开

<% 
Response.Buffer = true 
Response.Clear 

dim url 
Dim fso,fl,flsize 
dim Dname 
Dim objStream,ContentType,flName,isre,url1 
'*********************************************调用时传入的下载文件名 
Dname=trim(request("n")) 
'****************************************************************** 
If Dname<>"" Then 
'******************************下载文件存放的服务端目录 
 url=server.MapPath("/")&"\"&Dname 
'*************************************************** 
End If 

Set fso=Server.CreateObject("Scripting.FileSystemObject") 
 Set fl=fso.getfile(url) 
 flsize=fl.size 
 flName=fl.name 
 Set fl=Nothing 
 Set fso=Nothing 
%> 
<% 
 Set objStream = Server.CreateObject("ADODB.Stream") 
 objStream.Open 
 objStream.Type = 1 
 objStream.LoadFromFile url 


 Select Case lcase(Right(flName, 4)) 
 Case ".asf" 
  ContentType = "video/x-ms-asf" 
 Case ".avi" 
  ContentType = "video/avi" 
 Case ".doc" 
  ContentType = "application/msword" 
 Case ".zip" 
  ContentType = "application/zip" 
 Case ".xls" 
  ContentType = "application/vnd.ms-excel" 
 Case ".gif" 
  ContentType = "image/gif" 
 Case ".jpg", "jpeg" 
  ContentType = "image/jpeg" 
 Case ".wav" 
  ContentType = "audio/wav" 
 Case ".mp3" 
  ContentType = "audio/mpeg3" 
 Case ".mpg", "mpeg" 
  ContentType = "video/mpeg" 
 Case ".rtf" 
  ContentType = "application/rtf" 
 Case ".htm", "html" 
  ContentType = "text/html" 
 Case ".txt" 
  ContentType = "text/plain" 
 Case Else 
  ContentType = "application/octet-stream" 
 End Select 

 Response.AddHeader "Content-Disposition", "attachment; filename=" & flName 
 Response.AddHeader "Content-Length", flsize 

 Response.Charset = "UTF-8" 
 Response.ContentType = ContentType 

 Response.BinaryWrite objStream.Read 
 Response.Flush 
 response.Clear() 
 objStream.Close 
 Set objStream = Nothing 
%>

if instr(Request.ServerVariables("HTTP_REFERER"),"http://你的域名")=0 then 
   Response.End 
end if