DateTime dt=DateTime.Now;
string mytime=string.Format("{0:yyyy-MM-dd hh:mm:ss}",dt); 2013-4-12 11:47:34
DateTime.Now.ToLongDateString().ToString():2013年4月12日
DateTime.Now.ToShortDateString().ToString(): 2013-4-12DateTime.Now.ToLongTimeString().ToString(): 19:47:34
DateTime.Now.ToShortTimeString().ToString(): 19:47
DateTime.Now.ToUniversalTime().ToString(): 2013-4-12 11:47:34
DateTime.Now.ToLocalTime().ToString(): 2013-4-12 19:47:34
DateTime.Now.ToString(): 2013-4-12 19:47:34
DateTime.Now.Year.ToString(): 2013
DateTime.Now.Month.ToString(): 4
DateTime.Now.Day.ToString(): 12
DateTime.Now.Hour.ToString(): 19
DateTime.Now.Minute.ToString(): 47
DateTime.Now.Second.ToString(): 34
DateTime.Now.DayOfWeek.ToString(): Friday
DateTime.Now.DayOfYear.ToString(): 102 //一年中的第几天