DatetimeのC#での使い方現在の時間の様々なフォーマットを取得
DateTime
： DateTime dt = DateTime.Now;
Environment.TickCount “ ”
DateTime now = DateTime.Now;
Console.WriteLine(now.ToString("yyyy-MM-dd")); // yyyy-MM-dd s
Console.WriteLine(dt.ToString()); // 26/11/2009 AM 11:21:30
Console.WriteLine(dt.ToFileTime().ToString()); // 129036792908014024
// Converts the value of the current System.DateTime object to a Windows file time
Console.WriteLine(dt.ToFileTimeUtc().ToString()); // 129036792908014024
// Converts the value of the current System.DateTime object to a Windows file time
Console.WriteLine(dt.ToLocalTime().ToString()); // 26/11/2009 AM 11:21:30
// Converts the value of the current System.DateTime object to local time.
Console.WriteLine(dt.ToLongDateString().ToString()); // 2009 11 26
Console.WriteLine(dt.ToLongTimeString().ToString()); // AM 11:21:30
Console.WriteLine(dt.ToOADate().ToString()); // 40143.4732731597
Console.WriteLine(dt.ToShortDateString().ToString()); // 26/11/2009
Console.WriteLine(dt.ToShortTimeString().ToString()); // AM 11:21
Console.WriteLine(dt.ToUniversalTime().ToString()); // 26/11/2009 AM 3:21:30
Console.WriteLine(dt.Year.ToString()); // 2009
Console.WriteLine(dt.Date.ToString()); // 26/11/2009 AM 12:00:00
Console.WriteLine(dt.DayOfWeek.ToString()); // Thursday
Console.WriteLine(dt.DayOfYear.ToString()); // 330
Console.WriteLine(dt.Hour.ToString()); // 11
Console.WriteLine(dt.Millisecond.ToString()); // 801 （ ）
Console.WriteLine(dt.Minute.ToString()); // 21
Console.WriteLine(dt.Month.ToString()); // 11
Console.WriteLine(dt.Second.ToString()); // 30
Console.WriteLine(dt.Ticks.ToString()); // 633948312908014024
Console.WriteLine(dt.TimeOfDay.ToString()); // 12:29:51.5181524
// Gets the time of day for this instance.
// A System.TimeSpan that represents the fraction of the day that has elapsed since midnight.
Console.WriteLine(dt.ToString()); // 26/11/2009 PM 12:29:51
Console.WriteLine(dt.AddYears(1).ToString()); // 26/11/2010 PM 12:29:51
Console.WriteLine(dt.AddDays(1.1).ToString()); // 27/11/2009 PM 2:53:51
Console.WriteLine(dt.AddHours(1.1).ToString()); // 26/11/2009 PM 1:35:51
Console.WriteLine(dt.AddMilliseconds(1.1).ToString()); //26/11/2009 PM 12:29:51
Console.WriteLine(dt.AddMonths(1).ToString()); // 26/12/2009 PM 12:29:51
Console.WriteLine(dt.AddSeconds(1.1).ToString()); // 26/11/2009 PM 12:29:52
Console.WriteLine(dt.AddMinutes(1.1).ToString()); // 26/11/2009 PM 12:30:57
Console.WriteLine(dt.AddTicks(1000).ToString()); // 26/11/2009 PM 12:29:51
Console.WriteLine(dt.CompareTo(dt).ToString()); // 0
Console.WriteLine(dt.Add(new TimeSpan(1,0,0,0)).ToString()); //
（ ：
System.TimeSpan ，
public TimeSpan(long ticks); // ticks: A time period expressed in 100-nanosecond units.
//nanosecond： new TimeSpan(10,000,000)
public TimeSpan(int hours, int minutes, int seconds);
public TimeSpan(int days, int hours, int minutes, int seconds);
public TimeSpan(int days, int hours, int minutes, int seconds, int milliseconds);
）
Console.WriteLine(dt.Equals("2005-11-6 16:11:04").ToString()); // False
Console.WriteLine(dt.Equals(dt).ToString()); // True
Console.WriteLine(dt.GetHashCode().ToString()); // 1103291775
Console.WriteLine(dt.GetType().ToString()); // System.DateTime
Console.WriteLine(dt.GetTypeCode().ToString()); // DateTime
long Start = Environment.TickCount; //
long End = Environment.TickCount;
Console.WriteLine("Start is : "+Start);
Console.WriteLine("End is : "+End);
Console.WriteLine("The Time is {0}",End-Start);
Console.WriteLine(dt.GetDateTimeFormats('s')[0].ToString()); //2009-11-26T13:29:06
Console.WriteLine(dt.GetDateTimeFormats('t')[0].ToString()); //PM 1:29
Console.WriteLine(dt.GetDateTimeFormats('y')[0].ToString()); //2009 11
Console.WriteLine(dt.GetDateTimeFormats('D')[0].ToString()); //2009 11 26
Console.WriteLine(dt.GetDateTimeFormats('D')[1].ToString()); // , 26 , 2009
Console.WriteLine(dt.GetDateTimeFormats('D')[2].ToString()); //26 , 2009
Console.WriteLine(dt.GetDateTimeFormats('D')[3].ToString()); // 2009 11 26
Console.WriteLine(dt.GetDateTimeFormats('M')[0].ToString()); //26
Console.WriteLine(dt.GetDateTimeFormats('f')[0].ToString()); //2009 11 26 PM 1:29
Console.WriteLine(dt.GetDateTimeFormats('g')[0].ToString()); //26/11/2009 PM 1:29
Console.WriteLine(dt.GetDateTimeFormats('r')[0].ToString()); //Thu, 26 Nov 2009 13:29:06 GMT
( ：
：
d MM/dd/yyyy
D dddd, MMMM dd, yyyy
f (long date + short time) dddd, MMMM dd, yyyy HH:mm
F (long date + long time) dddd, MMMM dd, yyyy HH:mm:ss
g (short date + short time) MM/dd/yyyy HH:mm
G (short date + long time) MM/dd/yyyy HH:mm:ss
m,M MMMM dd
s yyyy-MM-dd HH:mm:ss
t HH:mm
T HH:mm:ss
)
Console.WriteLine(string.Format("{0:d}", dt)); //28/12/2009
Console.WriteLine(string.Format("{0:D}", dt)); //2009 12 28
Console.WriteLine(string.Format("{0:f}", dt)); //2009 12 28 AM 10:29
Console.WriteLine(string.Format("{0:F}", dt)); //2009 12 28 AM 10:29:18
Console.WriteLine(string.Format("{0:g}", dt)); //28/12/2009 AM 10:29
Console.WriteLine(string.Format("{0:G}", dt)); //28/12/2009 AM 10:29:18
Console.WriteLine(string.Format("{0:M}", dt)); //28
Console.WriteLine(string.Format("{0:R}", dt)); //Mon, 28 Dec 2009 10:29:18 GMT
Console.WriteLine(string.Format("{0:s}", dt)); //2009-12-28T10:29:18
Console.WriteLine(string.Format("{0:t}", dt)); //AM 10:29
Console.WriteLine(string.Format("{0:T}", dt)); //AM 10:29:18
Console.WriteLine(string.Format("{0:u}", dt)); //2009-12-28 10:29:18Z
Console.WriteLine(string.Format("{0:U}", dt)); //2009 12 28 AM 2:29:18
Console.WriteLine(string.Format("{0:Y}", dt)); //2009 12
Console.WriteLine(string.Format("{0}", dt)); //28/12/2009 AM 10:29:18
Console.WriteLine(string.Format("{0:yyyyMMddHHmmssffff}", dt)); //200912281029182047
2
DateTime dt1 = Convert.ToDateTime("2007-8-1");
DateTime dt2 = Convert.ToDateTime("2007-8-15");
TimeSpan span = dt2.Subtract(dt1);
int dayDiff = span.Days ;
int days = DateTime.DaysInMonth(2009, 8);
days = 31;
、
DateTime dt =DateTime.Now;
dt.AddDays(1); // dt
dt.AddDays(-1);// dt