if (filesxt.Extension.ToString()==".rar")
{
    NUnrar.Archive.RarArchive.WriteToDirectory(Sourcepath, Destination,
        NUnrar.Common.ExtractOptions.ExtractFullPath |
        NUnrar.Common.ExtractOptions.Overwrite);
}
else if (filesxt.Extension.ToString() == ".zip")
{
    UnZipFromMTAThread(Sourcepath, Destination);
}

ExtractFile(Sourcepath, Destination);