ASP. NET download file code block

/// <Summary>
/// Normal download
/// </Summary>
/// <Param name = "FileName"> Virtual File Path </param>
Public static void DownLoadold (string FileName)
{
String destFileName = FileName; // MapPathFile (FileName );
If (File. Exists (destFileName ))
{
FileInfo fi = new FileInfo (destFileName );
HttpContext. Current. Response. Clear ();
HttpContext. Current. Response. ClearHeaders ();
HttpContext. Current. Response. Buffer = false;
HttpContext. current. response. appendHeader ("Content-Disposition", "attachment; filename =" + HttpUtility. urlEncode (Path. getFileName (destFileName), System. text. encoding. UTF8 ));
HttpContext. Current. Response. AppendHeader ("Content-Length", fi. Length. ToString ());
HttpContext. Current. Response. ContentType = "application/octet-stream ";
HttpContext. Current. Response. WriteFile (destFileName );
HttpContext. Current. Response. Flush ();
HttpContext. Current. Response. End ();
}
}