public void DownloadSpreadSheet()
        {
            _Logger.WriteLine("[Download] Begin to download spread sheet.");
            var list = _ItemManager.GetAllItems();

            foreach (var item in list)
            {
                _Logger.WriteLine(string.Format("[Download] Processing \"{0}\"...", item.Name));

                string output = _Downloader.DownloadSpreadSheet(item.Key, item.Gid);
                _ItemManager.Write(item.FilePath, output);

                _Logger.WriteLine(string.Format("[Complete] Success to export \"{0}\".", item.FilePath));
            }

            _ItemManager.Dispose();
            _Logger.WriteLine("[Complete] All Table is Complete.");
        }