<%
Sub SaveFile(sFile)
    Dim sPath,objTs,objFso,F
    sPath = Server.MapPath(sFile)    
    Response.Buffer = True    
    Response.Clear    
    Set objTs = Server.CreateObject("ADODB.Stream")    
    objTs.Open    
    objTs.Type = 1    
    On  Error  Resume  Next    
    Set objFso = Server.CreateObject("Scripting.FileSystemObject")
    If Not objFso.FileExists(sPath) Then
        Response.Write("<h1>Error:</h1>"&sPath&"你要下载的文件不存在！<p>")    
        Response.End    
    End  If

    
    Set objFile = objFso.GetFile(sPath)    
    objTs.LoadFromFile(sPath)
    If Err Then    
        Response.Write("<h1>Error： </h1>Unknown Error！<p>")    
        Response.End
    End If  
    
    Response.AddHeader "Content-Disposition","attachment;filename="&objFile.name    
    Response.AddHeader "Content-Length",objFile.Size    
    Response.CharSet = "GB2312"    
    Response.ContentType = "application/octet-stream"    
    Response.BinaryWrite  objTs.Read    
    Response.Flush        
    objTs.Close    
    Set objTs = Nothing
End Sub

Call SaveFile("test.asp")
%>

<%@ WebHandler Language="C#" Class="Download" %>

using System;
using System.Web;
using System.IO;

public class Download : IHttpHandler {
    
    public void ProcessRequest (HttpContext context) {

        byte[] buffer;
        FileInfo file = new FileInfo(context.Server.MapPath("/rp Source.rar"));

        using (FileStream fs = new FileStream(file.FullName, FileMode.Open, FileAccess.Read))
        {
            buffer = new byte[fs.Length];
            fs.Read(buffer, 0, (int)fs.Length);
        }

        context.Response.ContentType = "application/octet-stream";
        context.Response.AddHeader("Content-Disposition", "attachment;FileName=" + file.Name);
        context.Response.AddHeader("Content-Length", file.Length.ToString());
        context.Response.BinaryWrite(buffer);
        context.Response.End();
        
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}