C# 获取当前时间戳

        /// <summary>
        /// 时间戳
        /// </summary>
        /// <param name="dateTime"></param>
        /// <returns></returns>
        public static Int64 getTimeStamp(DateTime dateTime)
        {
            TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
            return Convert.ToInt64(ts.TotalSeconds);
        }
        /// <summary>
        /// 时间戳转本地时间
        /// </summary>
        /// <param name="unixTimeStamp"></param>
        /// <returns></returns>
        public static DateTime getLocalDateTime(double unixTimeStamp)
        {

            System.DateTime startTime = TimeZone.CurrentTimeZone.ToLocalTime(new System.DateTime(1970, 1, 1)); //当地时区
            DateTime dtime = startTime.AddSeconds(unixTimeStamp);
            return dtime;
        }

https://www.cnblogs.com/yinmu/p/11228196.html

/// <summary>
        /// 获取时间戳
        /// </summary>
        /// <returns></returns>
        public string GetTimeStamp()
        {
            TimeSpan ts = DateTime.Now - new DateTime(1970, 1, 1, 0, 0, 0, 0);
            return Convert.ToInt64(ts.TotalSeconds).ToString();
        }

/// <summary>
        /// 获取时间戳
        /// </summary>
        /// <returns></returns>
        public static string GetTimeStamp()
        {
            TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
            return Convert.ToInt64(ts.TotalMilliseconds).ToString();
        }

把数据库存的double类型时间戳转成日期时间 （下面这个功能是遍历DataTable，把原有的addTime(时间戳)转为现有add_time日期字符串）

  　　　　　　DataColumn dc = null; //原来的数据上增加一列
            dc = dt.Columns.Add("add_time", Type.GetType("System.String")); //日期

            for (int i = 0; i < dt.Rows.Count; i++)
            {
                Console.WriteLine(dt.Rows[i]["addTime"].ToString());
                double unixTimeStamp = 0;
                if (dt.Rows[i]["addTime"].ToString().Trim() == null || dt.Rows[i]["addTime"].ToString().Trim() == "")
                {
                    unixTimeStamp = 0;
                }
                else
                {
                    unixTimeStamp = Convert.ToDouble(pe.dt.Rows[i]["addTime"].ToString());
                }  
                System.DateTime startTime = TimeZone.CurrentTimeZone.ToLocalTime(new System.DateTime(1970, 1, 1)); // 当地时区
                DateTime dtime = startTime.AddMilliseconds(unixTimeStamp);
                //dt.Rows[i]["addTime"] = dtime;//不能覆盖原来值，报错类型不一致，所以要新建一个row
                dt.Rows[i]["add_time"] = dtime.ToString("yyyy/MM/dd HH:mm:ss");

      
                //dt.Rows.Add(dr);//如果新实例化 DataRow dr = dt.NewRow(); 一个行，需要加入这行

            }

转： https://www.cnblogs.com/yinmu/p/11228196.html