关于下载路径的隐藏都是通过传递一个数据库中的ID，然后在另外一张页面通过传递的ID在数据库中读出路径。
1、c#中实现的方法（只需要.ASPX.CS的代码就可以了）
string sel_sql="select FileVisualPath from TabMailAttachFiles where FileID="+Request.QueryString["destFileName"].ToString();

//   string destFileName = Request.QueryString["destFileName"]!=null?Request.QueryString["destFileName"]:"";
   string destFileName=ROA.Components.fune_commerce.Execad(sel_sql).Tables[0].Rows[0][0].ToString();
   destFileName = Server.MapPath(".")+destFileName;
   destFileName = Server.UrlDecode(destFileName);
   if(File.Exists(destFileName))
   {
    FileInfo fi = new FileInfo(destFileName);
    Response.Clear();
    Response.ClearHeaders();
    Response.Buffer = false;
   
    //Response.AppendHeader("Content-Disposition","attachment;filename=" +HttpUtility.UrlEncode(Path.GetFileName(destFileName),System.Text.Encoding.Default));
    Response.AppendHeader("Content-Disposition","attachment;filename=" +HttpUtility.UrlEncode(Path.GetFileName(destFileName),System.Text.Encoding.UTF8));
    Response.AppendHeader("Content-Length",fi.Length.ToString());
    Response.ContentType="application/octet-stream";
    Response.WriteFile(destFileName);
    Response.Flush();
    Response.End();
   }
   else
   {
    Response.Write("<script langauge=javascript>alert(文件不存在!);history.go(-1);</script>");
    Response.End();
   }
2、在ASP中的实现方法
<!--#include file="conn.asp" -->
<%
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
m_ID=trim(request.QueryString("ID"))
set rs=Server.CreateObject("adodb.recordset")
sql="select * from dataview where xsf=true and id="&m_ID
rs.open sql,conn,1,1
if not rs.eof then
    Dname=rs("path")
else
    Response.Write("no found")
    Response.end
end if
rs.close:set rs=nothing
******************************************************************
If Dname<>"" Then
******************************下载文件存放的服务端目录
url=Server.MapPath(Dname)
else
    Response.Write("no found")
    Response.end 
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 ".bmp"
ContentType = "image/bmp"
Case ".ppt"
ContentType = "application/vnd.ms-powerpoint"
Case ".mdb"
ContentType = "application/x-msaccess"
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
%>

出处：『 漂失在蓝天下的云 』 BLOG