DateTime.DayOfYear 屬性

定義

命名空間:

System

組件:

System.Runtime.dll

Source:

DateTime.cs

取得由這個執行個體表示的一年天數。

public:
 property int DayOfYear { int get(); };

public int DayOfYear { get; }

member this.DayOfYear : int

Public ReadOnly Property DayOfYear As Integer

屬性值

Int32

一年中的日期，以 1 到 366 之間的值表示。

範例

下列範例會顯示西曆中 2010 年 2010-2020 年 12 月 31 日的日期。 請注意，此範例顯示 12 月 31 日是閏年的第 366 天。

using System;

public class Example
{
   public static void Main()
   {
      DateTime dec31 = new DateTime(2010, 12, 31);
      for (int ctr = 0; ctr <= 10; ctr++) {
         DateTime dateToDisplay = dec31.AddYears(ctr);
         Console.WriteLine("{0:d}: day {1} of {2} {3}", dateToDisplay,
                           dateToDisplay.DayOfYear,
                           dateToDisplay.Year,
                           DateTime.IsLeapYear(dateToDisplay.Year) ?
                                               "(Leap Year)" : "");
      }
   }
}
// The example displays the following output:
//       12/31/2010: day 365 of 2010
//       12/31/2011: day 365 of 2011
//       12/31/2012: day 366 of 2012 (Leap Year)
//       12/31/2013: day 365 of 2013
//       12/31/2014: day 365 of 2014
//       12/31/2015: day 365 of 2015
//       12/31/2016: day 366 of 2016 (Leap Year)
//       12/31/2017: day 365 of 2017
//       12/31/2018: day 365 of 2018
//       12/31/2019: day 365 of 2019
//       12/31/2020: day 366 of 2020 (Leap Year)

open System

let dec31 = DateTime(2010, 12, 31)
for i = 0 to 10 do
    let dateToDisplay = dec31.AddYears i
    let leap = if DateTime.IsLeapYear dateToDisplay.Year then "(Leap Year)" else ""
    printfn $"{dateToDisplay:d}: day {dateToDisplay.DayOfYear} of {dateToDisplay.Year} {leap}"

// The example displays the following output:
//       12/31/2010: day 365 of 2010
//       12/31/2011: day 365 of 2011
//       12/31/2012: day 366 of 2012 (Leap Year)
//       12/31/2013: day 365 of 2013
//       12/31/2014: day 365 of 2014
//       12/31/2015: day 365 of 2015
//       12/31/2016: day 366 of 2016 (Leap Year)
//       12/31/2017: day 365 of 2017
//       12/31/2018: day 365 of 2018
//       12/31/2019: day 365 of 2019
//       12/31/2020: day 366 of 2020 (Leap Year)

Option Strict On

Module Example
   Public Sub Main()
      Dim dec31 As Date = #12/31/2010#
      For ctr As Integer = 0 To 10
         Dim dateToDisplay As Date = dec31.AddYears(ctr)
         Console.WriteLine("{0:d}: day {1} of {2} {3}", dateToDisplay, 
                           dateToDisplay.DayOfYear,
                           dateToDisplay.Year,   
                           If(DateTime.IsLeapYear(dateToDisplay.Year), 
                                                  "(Leap Year)", "")) 
                           
      Next
   End Sub
End Module
' The example displays the following output:
'       12/31/2010: day 365 of 2010
'       12/31/2011: day 365 of 2011
'       12/31/2012: day 366 of 2012 (Leap Year)
'       12/31/2013: day 365 of 2013
'       12/31/2014: day 365 of 2014
'       12/31/2015: day 365 of 2015
'       12/31/2016: day 366 of 2016 (Leap Year)
'       12/31/2017: day 365 of 2017
'       12/31/2018: day 365 of 2018
'       12/31/2019: day 365 of 2019
'       12/31/2020: day 366 of 2020 (Leap Year)

備註

當屬性計算年份的日期時，屬性 DayOfYear 會將閏年納入考慮。 不論目前文化特性的目前行事曆為何，屬性值一律會反映西曆中的年份日期。 若要在不同的日曆中擷取年份的日期，請呼叫 Calendar.GetDayOfYear 該行事曆的 方法。

另請參閱

• GetDayOfYear(DateTime)