取得文件后缀

#region 取得文件后缀
        /************************************
         * 函数名称:GetFileExtends
         * 功能说明:取得文件后缀
         * 参    数:filename:文件名称
         * 调用示例:
         *          GetRemoteObj o = new GetRemoteObj();
         *          string url = @"http://www.baidu.com/img/logo.gif";
         *          string s = o.GetFileExtends(url);
         *          Response.Write(s);
         *          o.Dispose();
         * ********************************/
        /**//**//**//// <summary>
        /// 取得文件后缀
        /// </summary>
        /// <param name="filename">文件名称</param>
        /// <returns></returns>
        public string GetFileExtends(string filename)
        ...{
            string ext = null;
            if (filename.IndexOf('.') > 0)
            ...{
                string[] fs = filename.Split('.');
                ext = fs[fs.Length - 1];
            }
            return ext;
        }
        #endregion

文章出处：http://www.diybl.com/course/4_webprogram/asp.net/netjs/2007113/82428.html