protected override void InvokeOnCanRetrieveFile(FtpTransferEventArgs e)
{
VirtualFtpSession lSession = (VirtualFtpSession)e.Session;
IFtpFolder lFolder;
String lFilename;
lSession.CurrentFolder.FindBaseFolderForFilename(e.FileName, out lFolder, out lFilename, lSession);
IFtpFile lFile = lFolder.GetFile(lFilename, lSession);
e.Ok = (lFile != null && lFile.AllowRead(lSession));
}