文件下载

 string Path = Request.PhysicalApplicationPath + "App_Data" + "\\" + "aaa.mdb";
        FileInfo info = new FileInfo( Path );
        if( info.Exists )
        {
            Response.Clear();
            Response.ClearHeaders();
            Response.Buffer = false;
            Response.ContentType = "Application/octet-stream";           
            Response.AddHeader( "Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode( info.FullName, Encoding.UTF8 ) );
            Response.WriteFile( info.FullName );
            Response.Flush();
            Response.End();
        }