DateTime.DaysInMonth(Int32, Int32) DateTime.DaysInMonth(Int32, Int32) DateTime.DaysInMonth(Int32, Int32) DateTime.DaysInMonth(Int32, Int32) Method

定义

返回指定年和月中的天数。Returns the number of days in the specified month and year.

public:
 static int DaysInMonth(int year, int month);
public static int DaysInMonth (int year, int month);
static member DaysInMonth : int * int -> int
Public Shared Function DaysInMonth (year As Integer, month As Integer) As Integer

参数

year
Int32 Int32 Int32 Int32

年。The year.

month
Int32 Int32 Int32 Int32

月(介于 1 到 12 之间的一个数字)。The month (a number ranging from 1 to 12).

返回

指定 monthyear 中的天数。The number of days in month for the specified year.

例如,如果 month 等于 2(表示二月),则返回值为 28 或 29,具体取决于 year 是否为闰年。For example, if month equals 2 for February, the return value is 28 or 29 depending upon whether year is a leap year.

异常

month 小于 1 或大于 12。month is less than 1 or greater than 12.

-or- year 小于 1 或大于 9999。year is less than 1 or greater than 9999.

示例

下面的示例演示如何使用DaysInMonth方法来确定2001年 1998 2 月(非闰年)和2月1996(闰年)中的天数。The following example demonstrates how to use the DaysInMonth method to determine the number of days in July 2001, February 1998 (a non-leap year), and February 1996 (a leap year).

using namespace System;

int main()
{
   const int July = 7;
   const int Feb = 2;
   
   int daysInJuly = System::DateTime::DaysInMonth( 2001, July );
   Console::WriteLine(daysInJuly);   
   // daysInFeb gets 28 because the year 1998 was not a leap year.
   int daysInFeb = System::DateTime::DaysInMonth( 1998, Feb );
   Console::WriteLine(daysInFeb);
   // daysInFebLeap gets 29 because the year 1996 was a leap year.
   int daysInFebLeap = System::DateTime::DaysInMonth( 1996, Feb );
   Console::WriteLine(daysInFebLeap);
}
// The example displays the following output:
//       31
//       28
//       29
using System;

class Example
{
    static void Main()
    {
        const int July = 7;
        const int Feb = 2;

        int daysInJuly = System.DateTime.DaysInMonth(2001, July);
        Console.WriteLine(daysInJuly);
        
        // daysInFeb gets 28 because the year 1998 was not a leap year.
        int daysInFeb = System.DateTime.DaysInMonth(1998, Feb);
        Console.WriteLine(daysInFeb);
        
        // daysInFebLeap gets 29 because the year 1996 was a leap year.
        int daysInFebLeap = System.DateTime.DaysInMonth(1996, Feb);
        Console.WriteLine(daysInFebLeap);
    }
}
// The example displays the following output:
//       31
//       28
//       29
Class Example
   Public Shared Sub Main()
      Const July As Integer = 7
      Const Feb As Integer = 2

      Dim daysInJuly As Integer = System.DateTime.DaysInMonth(2001, July)
      Console.WriteLine(daysInJuly)
      
      ' daysInFeb gets 28 because the year 1998 was not a leap year.
      Dim daysInFeb As Integer = System.DateTime.DaysInMonth(1998, Feb)
      Console.WriteLine(daysInFeb)
      ' daysInFebLeap gets 29 because the year 1996 was a leap year.
      Dim daysInFebLeap As Integer = System.DateTime.DaysInMonth(1996, Feb)
      Console.WriteLine(daysInFebLeap)
   End Sub
End Class
' The example displays the following output:
'       31
'       28
'       29

下面的示例显示在一个整数数组中指定的一年中每个月的天数。The following example displays the number of days in each month of a year specified in an integer array.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      int[] years = { 2012, 2014 };
      DateTimeFormatInfo dtfi = DateTimeFormatInfo.CurrentInfo;
      Console.WriteLine("Days in the Month for the {0} culture " +
                        "using the {1} calendar\n", 
                        CultureInfo.CurrentCulture.Name, 
                        dtfi.Calendar.GetType().Name.Replace("Calendar", ""));
      Console.WriteLine("{0,-10}{1,-15}{2,4}\n", "Year", "Month", "Days");
      
      foreach (var year in years) {
         for (int ctr = 0; ctr <= dtfi.MonthNames.Length - 1; ctr++) {
            if (String.IsNullOrEmpty(dtfi.MonthNames[ctr]))  
               continue;
            
            Console.WriteLine("{0,-10}{1,-15}{2,4}", year, 
                              dtfi.MonthNames[ctr], 
                              DateTime.DaysInMonth(year, ctr + 1));
         }
         Console.WriteLine(); 
      }
   }
}
// The example displays the following output:
//    Days in the Month for the en-US culture using the Gregorian calendar
//    
//    Year      Month          Days
//    
//    2012      January          31
//    2012      February         29
//    2012      March            31
//    2012      April            30
//    2012      May              31
//    2012      June             30
//    2012      July             31
//    2012      August           31
//    2012      September        30
//    2012      October          31
//    2012      November         30
//    2012      December         31
//    
//    2014      January          31
//    2014      February         28
//    2014      March            31
//    2014      April            30
//    2014      May              31
//    2014      June             30
//    2014      July             31
//    2014      August           31
//    2014      September        30
//    2014      October          31
//    2014      November         30
//    2014      December         31
Imports System.Globalization

Module Example
   Public Sub Main()
      Dim years() As Integer = { 2012, 2014 }
      Dim dtfi As DateTimeFormatInfo = DateTimeFormatInfo.CurrentInfo
      Console.WriteLine("Days in the Month for the {0} culture " +
                        "using the {1} calendar", 
                        CultureInfo.CurrentCulture.Name, 
                        dtfi.Calendar.GetType.Name.Replace("Calendar", ""))
      Console.WriteLine()
      Console.WriteLine("{0,-10}{1,-15}{2,4}", "Year", "Month", "Days")
      Console.WriteLine()
      
      For Each [year] As Integer In years
         For ctr As Integer = 0 To dtfi.MonthNames.Length - 1
            If String.IsNullOrEmpty(dtfi.MonthNames(ctr)) Then 
               Continue For
            End If    
            
            Console.WriteLine("{0,-10}{1,-15}{2,4}", [year], 
                              dtfi.MonthNames(ctr), 
                              DateTime.DaysInMonth([year], ctr + 1))
         Next
         Console.WriteLine() 
      Next
   End Sub
End Module
' The example displays the following output:
'    Days in the Month for the en-US culture using the Gregorian calendar
'    
'    Year      Month          Days
'    
'    2012      January          31
'    2012      February         29
'    2012      March            31
'    2012      April            30
'    2012      May              31
'    2012      June             30
'    2012      July             31
'    2012      August           31
'    2012      September        30
'    2012      October          31
'    2012      November         30
'    2012      December         31
'    
'    2014      January          31
'    2014      February         28
'    2014      March            31
'    2014      April            30
'    2014      May              31
'    2014      June             30
'    2014      July             31
'    2014      August           31
'    2014      September        30
'    2014      October          31
'    2014      November         30
'    2014      December         31

注解

即使DaysInMonth公历不是month当前year区域性的当前日历,该方法也会将和解释为公历的月份和年份。The DaysInMonth method always interprets month and year as the month and year of the Gregorian calendar even if the Gregorian calendar is not the current culture's current calendar. 若要获取特定日历的指定月份中的天数,请调用该日历的GetDaysInMonth方法。To get the number of days in a specified month of a particular calendar, call that calendar's GetDaysInMonth method.

适用于