/// <summary>
        /// 设置下载路径
        /// </summary>
        /// <returns></returns>
        private string SetDirectory()
        {
            // 下载目录
            string path;

            // 弹出选择下载目录的窗口
            path = DialogUtils.SetDownloadDirectory();
            if (path == null || path == string.Empty)
            {
                return(null);
            }

            return(path);
        }