public bool IfTime(string StartTime, string EndTime)        {            DateTime dt1 = Convert.ToDateTime(StartTime);            DateTime dt2 = Convert.ToDateTime(EndTime);            if (DateTime.Compare(dt1, dt2) < 0)            {                //开始时间 < 结束时间 (执行以下语句),,说明开始时间晚                return true;            }            return false;        }

starttime= DateTime.Now.ToShortTimeString().ToString();

 

/// 
        /// 获得固定年月日,时和分不固定 : 2019-01-01 00:00:00        /// 
        /// 
              public DateTime GetFixedDateTime()        {            string time1 = DateTime.Now.ToShortTimeString(); //16:50            //yyyy-MM-dd hh:mm:ss //2019-01-01 16:34:00            string Ymd = "2019-01-01 ";            string Hour = DateTime.Now.Hour.ToString();            string Minute = DateTime.Now.Minute.ToString();            return Convert.ToDateTime(Ymd + Hour + ":" + Minute + ":" + 00);        }

 

/// 
        /// 获得固定年月日,时和分不固定 : 2019-01-01 00:00:00        /// 
        /// 
              public DateTime GetFixedDateTime(string Hour = "", string Minute = "")        {            string time1 = DateTime.Now.ToShortTimeString(); //16:50            //yyyy-MM-dd hh:mm:ss //2019-01-01 16:34:00            string Ymd = "2019-01-01 ";            if (Hour == "")            {                Hour = DateTime.Now.Hour.ToString();                Minute = DateTime.Now.Minute.ToString();            }            return Convert.ToDateTime(Ymd + Hour + ":" + Minute + ":" + 00);        }