Datatime dt = new datatime (); // dt 为时间 datatime 对象
dt.toString (); // 2005-11-5 13:47:04
dt.addyears (1) .toString (); // 2006-11-5 13:47:04
dt.adddays (1.1) .toString (); // 2005-11-6 16:11:04
DT.AddHours (1.1) .ToString (); // 2005-11-5 14:53:04
dt.addmilliseconds (1.1) .toString (); // 2005-11-5 13:47:04
dt.addmonths (1) .toString (); // 2005-12-5 13:47:04
DT.AddDeconds (1.1) .ToString (); // 2005-11-5 13:47:05
dt.addMinutes (1.1) .ToString (); // 2005-11-5 13:48:10
dt.addticks (1000) .toString (); // 2005-11-5 13:47:04