Calendar.GetWeekOfYear(DateTime, CalendarWeekRule, DayOfWeek) 方法

定义

命名空间:

System.Globalization

程序集:

System.Runtime.dll

Source:

Calendar.cs

返回一年中包含指定 DateTime 值中的日期的那个星期。

public:
 virtual int GetWeekOfYear(DateTime time, System::Globalization::CalendarWeekRule rule, DayOfWeek firstDayOfWeek);

public virtual int GetWeekOfYear (DateTime time, System.Globalization.CalendarWeekRule rule, DayOfWeek firstDayOfWeek);

abstract member GetWeekOfYear : DateTime * System.Globalization.CalendarWeekRule * DayOfWeek -> int
override this.GetWeekOfYear : DateTime * System.Globalization.CalendarWeekRule * DayOfWeek -> int

Public Overridable Function GetWeekOfYear (time As DateTime, rule As CalendarWeekRule, firstDayOfWeek As DayOfWeek) As Integer

参数

time

DateTime

日期和时间值。

rule

CalendarWeekRule

定义日历周的枚举值。

firstDayOfWeek

DayOfWeek

表示一周的第一天的枚举值。

返回

Int32

一个正整数，用于表示一年中包含 time 参数内日期所在的星期。

例外

ArgumentOutOfRangeException

time 早于 MinSupportedDateTime 或晚于 MaxSupportedDateTime。

- 或 -

firstDayOfWeek 不是有效的 DayOfWeek 值。

- 或 -

rule 不是有效的 CalendarWeekRule 值。

示例

下面的代码示例演示 的结果 GetWeekOfYear 如何因 FirstDayOfWeek 使用的 和 CalendarWeekRule 而异。 如果指定的日期是一年中的最后一天， GetWeekOfYear 则 返回该年的总周数。

using namespace System;
using namespace System::Globalization;
int main()
{
   
   // Gets the Calendar instance associated with a CultureInfo.
   CultureInfo^ myCI = gcnew CultureInfo( "en-US" );
   Calendar^ myCal = myCI->Calendar;
   
   // Gets the DTFI properties required by GetWeekOfYear.
   CalendarWeekRule myCWR = myCI->DateTimeFormat->CalendarWeekRule;
   DayOfWeek myFirstDOW = myCI->DateTimeFormat->FirstDayOfWeek;
   
   // Displays the number of the current week relative to the beginning of the year.
   Console::WriteLine( "The CalendarWeekRule used for the en-US culture is {0}.", myCWR );
   Console::WriteLine( "The FirstDayOfWeek used for the en-US culture is {0}.", myFirstDOW );
   Console::WriteLine( "Therefore, the current week is Week {0} of the current year.", myCal->GetWeekOfYear( DateTime::Now, myCWR, myFirstDOW ) );
   
   // Displays the total number of weeks in the current year.
   DateTime LastDay = System::DateTime( DateTime::Now.Year, 12, 31 );
   Console::WriteLine( "There are {0} weeks in the current year ( {1}).", myCal->GetWeekOfYear( LastDay, myCWR, myFirstDOW ), LastDay.Year );
}

/*
This code produces the following output.  Results vary depending on the system date.

The CalendarWeekRule used for the en-US culture is FirstDay.
The FirstDayOfWeek used for the en-US culture is Sunday.
Therefore, the current week is Week 1 of the current year.
There are 53 weeks in the current year (2001).
*/

using System;
using System.Globalization;

public class SamplesCalendar  {

   public static void Main()  {

      // Gets the Calendar instance associated with a CultureInfo.
      CultureInfo myCI = new CultureInfo("en-US");
      Calendar myCal = myCI.Calendar;

      // Gets the DTFI properties required by GetWeekOfYear.
      CalendarWeekRule myCWR = myCI.DateTimeFormat.CalendarWeekRule;
      DayOfWeek myFirstDOW = myCI.DateTimeFormat.FirstDayOfWeek;

      // Displays the number of the current week relative to the beginning of the year.
      Console.WriteLine( "The CalendarWeekRule used for the en-US culture is {0}.", myCWR );
      Console.WriteLine( "The FirstDayOfWeek used for the en-US culture is {0}.", myFirstDOW );
      Console.WriteLine( "Therefore, the current week is Week {0} of the current year.", myCal.GetWeekOfYear( DateTime.Now, myCWR, myFirstDOW ));

      // Displays the total number of weeks in the current year.
      DateTime LastDay = new System.DateTime( DateTime.Now.Year, 12, 31 );
      Console.WriteLine( "There are {0} weeks in the current year ({1}).", myCal.GetWeekOfYear( LastDay, myCWR, myFirstDOW ), LastDay.Year );
   }
}

/*
This code produces the following output.  Results vary depending on the system date.

The CalendarWeekRule used for the en-US culture is FirstDay.
The FirstDayOfWeek used for the en-US culture is Sunday.
Therefore, the current week is Week 1 of the current year.
There are 53 weeks in the current year (2001).

*/

Imports System.Globalization

Public Class SamplesCalendar

   Public Shared Sub Main()
      
      ' Gets the Calendar instance associated with a CultureInfo.
      Dim myCI As New CultureInfo("en-US")
      Dim myCal As Calendar = myCI.Calendar
      
      ' Gets the DTFI properties required by GetWeekOfYear.
      Dim myCWR As CalendarWeekRule = myCI.DateTimeFormat.CalendarWeekRule
      Dim myFirstDOW As DayOfWeek = myCI.DateTimeFormat.FirstDayOfWeek
      
      ' Displays the number of the current week relative to the beginning of the year.
      Console.WriteLine("The CalendarWeekRule used for the en-US culture is {0}.", myCWR)
      Console.WriteLine("The FirstDayOfWeek used for the en-US culture is {0}.", myFirstDOW)
      Console.WriteLine("Therefore, the current week is Week {0} of the current year.", myCal.GetWeekOfYear(DateTime.Now, myCWR, myFirstDOW))
      
      ' Displays the total number of weeks in the current year.
      Dim LastDay = New System.DateTime(DateTime.Now.Year, 12, 31)
      Console.WriteLine("There are {0} weeks in the current year ({1}).", myCal.GetWeekOfYear(LastDay, myCWR, myFirstDOW), LastDay.Year)
   End Sub
End Class


'This code produces the following output.  Results vary depending on the system date.
'
'The CalendarWeekRule used for the en-US culture is FirstDay.
'The FirstDayOfWeek used for the en-US culture is Sunday.
'Therefore, the current week is Week 1 of the current year.
'There are 53 weeks in the current year (2001).

注解

此方法可用于通过将 设置为 time 一年中的最后一天来确定一年中的周数。

DateTimeFormatInfo使用 属性指示DateTimeFormatInfo.Calendar的日历的特定区域性的 对象包括可用于 和 firstDayOfWeek 参数的以下区域性特定值rule：

• 属性 DateTimeFormatInfo.FirstDayOfWeek 包含可用于 firstDayOfWeek 参数的默认一周的第一天。

• 属性 DateTimeFormatInfo.CalendarWeekRule 包含可用于 rule 参数的默认日历周规则。

注意

这不会完全映射到 ISO 8601。 Microsoft .NET 中的博客文章 ISO 8601 Year 周格式中讨论了这些差异。 从 .NET Core 3.0 开始， ISOWeek.GetYear 并 ISOWeek.GetWeekOfYear 解决此问题。

以下示例使用当前区域性的 DateTimeFormatInfo 对象来确定 2011 年 1 月 1 日是公历中每年的第一周。

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      DateTimeFormatInfo dfi = DateTimeFormatInfo.CurrentInfo;
      DateTime date1 = new DateTime(2011, 1, 1);
      Calendar cal = dfi.Calendar;

      Console.WriteLine("{0:d}: Week {1} ({2})", date1,
                        cal.GetWeekOfYear(date1, dfi.CalendarWeekRule,
                                          dfi.FirstDayOfWeek),
                        cal.ToString().Substring(cal.ToString().LastIndexOf(".") + 1));
   }
}
// The example displays the following output:
//       1/1/2011: Week 1 (GregorianCalendar)

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim dfi As DateTimeFormatInfo = DateTimeFormatInfo.CurrentInfo
      Dim date1 As Date = #1/1/2011#
      Dim cal As Calendar = dfi.Calendar
      
      Console.WriteLine("{0:d}: Week {1} ({2})", date1, 
                        cal.GetWeekOfYear(date1, dfi.CalendarWeekRule, 
                                          dfi.FirstDayOfWeek),
                        cal.ToString().Substring(cal.ToString().LastIndexOf(".") + 1))       
   End Sub
End Module
' The example displays the following output:
'       1/1/2011: Week 1 (GregorianCalendar)

对于某些日历，GetWeekOfYear调用 方法会为 和 firstDayOfWeek 值的特定组合rule引发 ，ArgumentOutOfRangeException即使 time 大于该日历的 属性返回的MinSupportedDateTime日期也是如此。 下表列出了受影响的日历、特定 rule 值以及最早支持 time 的值的范围。 特定的最小值 DateTime 取决于 参数的值 firstDayOfWeek 。

日历	CalendarWeekRule 值	公历日期 (M/dd/yyyy)	日历中的日期 (M/dd/yyyy)
ChineseLunisolarCalendar	FirstFullWeek	1901/2/19 至 2/25/1901	1901/1/1 至 1901/1/7
ChineseLunisolarCalendar	FirstFourDayWeek	1901/2/19 至 2/22/1901	1901/1/01 至 1901/1/04
HebrewCalendar	FirstDay	9/17/1583	1/01/5344
HebrewCalendar	FirstFullWeek	1583/9/17 至 1583/9/23	1/01/5344 到 1/07/5344
HebrewCalendar	FirstFourDayWeek	1583/9/17 至 1583/9/20	1/01/5344 到 1/04/5344
HijriCalendar	FirstFullWeek	7/18/0622 至 7/24/0622	1/01/0001 至 1/07/0001
HijriCalendar	FirstFourDayWeek	7/18/0622 至 7/21/0622	1/01/0001 至 1/04/0001
JapaneseLunisolarCalendar	FirstFullWeek	1/28/1960 至 2/03/1960	1/01/35 至 1/07/0035
JapaneseLunisolarCalendar	FirstFourDayWeek	1/28/1960 至 1/31/1960	1/01/0035 至 1/04/0035
JulianCalendar	FirstFullWeek	1/01/0001 至 1/05/0001	1/03/0001 至 1/07/0001
JulianCalendar	FirstFourDayWeek	1/01/0001 到 1/02/0001	1/03/0001 至 1/04/0001
KoreanLunisolarCalendar	FirstFullWeek	2/14/0918 至 2/20/0918	1/01/0918 至 1/07/0918
KoreanLunisolarCalendar	FirstFourDayWeek	2/14/0918 至 2/17/0918	1/01/0918 至 1/04/0918
PersianCalendar	FirstFullWeek	3/21/0622 至 3/27/0622	1/01/0001 至 1/07/0001
PersianCalendar	FirstFourDayWeek	3/21/0622 至 3/24/0622	1/01/0001 至 1/04/0001
TaiwanLunisolarCalendar	FirstFullWeek	2/18/1912 至 2/24/1912	1/01/0001 至 1/07/0001
TaiwanLunisolarCalendar	FirstFourDayWeek	2/18/1912 至 2/21/1912	1/01/0001 至 1/04/0001
UmAlQuraCalendar	FirstFullWeek	4/30/1900 至 5/06/1900	1/01/1318 至 1/07/1318
UmAlQuraCalendar	FirstFourDayWeek	4/30/1900 至 5/03/1900	1/01/1318 至 1/04/1318

另请参阅

• DateTime
• CalendarWeekRule
• DayOfWeek
• GetEra(DateTime)
• GetYear(DateTime)
• GetMonth(DateTime)
• GetDayOfYear(DateTime)
• GetDayOfMonth(DateTime)
• GetDayOfWeek(DateTime)
• GetHour(DateTime)
• GetMinute(DateTime)
• GetSecond(DateTime)
• GetMilliseconds(DateTime)