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.AddSegunds (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