获取当前时间戳

/// <summary>  
        /// 获取当前时间戳  
        /// </summary>  
        /// <param name="bflag">为真时获取10位时间戳,为假时获取13位时间戳.</param>  
        /// <returns></returns>  
        public static string getTimeStamp(bool bflag = true)
        {
            TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
            string ret = string.Empty;
            if (bflag)
                ret = Convert.ToInt64(ts.TotalSeconds).ToString();
            else
                ret = Convert.ToInt64(ts.TotalMilliseconds).ToString();

            return ret;
        }