標準日期和時間格式字串使用單一格式規範,定義日期和時間值的文字表示。
任何包含一個以上字元(包含空白字元)的日期和時間格式字串都會解譯為自訂日期和時間格式字串,自訂日期和時間格式字串可以搭配日期和時間執行個體的 ToString 方法或是支援複合格式的方法使用。
文法:(參數大小寫解譯不同 MM=month, mm=Minutes, HH=24hours, hh=12hours)
DateTime myDate = DateTime.Now; string myDateString = myDate.ToString("yyyy-MM-dd HH:mm:ss");
2011-10-16 02:33:54
DateTime dt = Convert.ToDateTime(myDateString);
2011/10/16 上午 02:33:54
DateTime sDate = Convert.ToDateTime("2010-10-15 15:50:39"); DateTime eDate = Convert.ToDateTime("2010-10-25 15:50:39"); TimeSpan ts = sDate - eDate; double days = ts.TotalDays; TextBox.Text = "差距 " + Convert.ToInt32(days).ToString() + "天";
差距 -10 天
DateTime dt = DateTime.Now; 取得目前日期時間
DateTime startWeek = dt.AddDays(1-Convert.ToInt32(dt.DayOfWeek.ToString("d")));
DateTime endWeek = startWeek.AddDays(6);
DateTime startMonth = dt.AddDays(1 - dt.Day);
DateTime endMonth = startMonth.AddMonths(1).AddDays(-1);
DateTime startQuarter = dt.AddMonths(0-(dt.Month-1) % 3).AddDays(1-dt.Day);
DateTime endQuarter = startQuarter.AddMonths(3).AddDays(-1);
DateTime startYear = new DateTime(dt.Year, 1, 1);
DateTime endYear = new DateTime(dt.Year, 12, 31);
startBeforeYear = DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")) .AddYears(-1).ToShortDateString();
endBeforeYear = DateTime.Parse(DateTime.Now.ToString("yyyy-12-31")) .AddDays(-1).ToShortDateString();
dateTimePickerStart.Value = DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")); dateTimePickerEnd.Value = DateTime.Now;
startNextYear = DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")) .AddYears(1).ToShortDateString();
endNextYear = DateTime.Parse(DateTime.Now.ToString("yyyy-12-31")) .AddYears(2).AddDays(-1).ToShortDateString();
dateTimePickerStart.Value = DateTime.Parse(DateTime.Now.ToString("yyyy-01-01")).AddYears(-1); dateTimePickerEnd.Value = DateTime.Parse(DateTime.Now.ToString("yyyy-12-31")).AddYears(-1);