• Article

Calendar.IsLeapMonth Method (Int32, Int32)

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Determines whether the specified month in the specified year in the current era is a leap month.

Namespace:  System.Globalization
Assembly:  mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Overridable Function IsLeapMonth ( _
    year As Integer, _
    month As Integer _
) As Boolean

public virtual bool IsLeapMonth(
    int year,
    int month
)

Parameters

  • year
    Type: System.Int32
    An integer that represents the year.
  • month
    Type: System.Int32
    A positive integer that represents the month.

Return Value

Type: System.Boolean
true if the specified month is a leap month; otherwise, false.

Exceptions

Exception Condition
ArgumentOutOfRangeException

year is outside the range supported by the calendar.

-or-

month is outside the range supported by the calendar.

Remarks

To make up for the difference between the calendar year and the actual time that the earth rotates around the sun or the actual time that the moon rotates around the earth, a leap year has a different number of days from a standard calendar year. Each Calendar implementation defines leap years differently.

A leap month is an entire month that occurs only in a leap year. For example, in the Hebrew calendar, Adar Beit is the only leap month.

Examples

The following code example compares different implementations of the Calendar class.

Imports System.Globalization

Public Class Example
   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' Creates an instance of every Calendar type.
      Dim myCals(6) As Calendar
      myCals(0) = New GregorianCalendar()
      myCals(1) = New HebrewCalendar()
      myCals(2) = New HijriCalendar()
      myCals(3) = New JapaneseCalendar()
      myCals(4) = New KoreanCalendar()
      myCals(5) = New TaiwanCalendar()
      myCals(6) = New ThaiBuddhistCalendar()

      ' For each calendar, displays the current year, the number of months in that year,
      ' and the number of days in each month of that year.
      Dim i, j, iYear, iMonth, iDay As Integer
      Dim myDT As DateTime = DateTime.Today

      For i = 0 To myCals.Length - 1
         iYear = myCals(i).GetYear(myDT)
         outputBlock.Text &= vbCrLf
         outputBlock.Text += String.Format("{0}, Year: {1}", myCals(i).GetType(), myCals(i).GetYear(myDT)) & vbCrLf
         outputBlock.Text += String.Format("   MonthsInYear: {0}", myCals(i).GetMonthsInYear(iYear)) & vbCrLf
         outputBlock.Text += String.Format("   DaysInYear: {0}", myCals(i).GetDaysInYear(iYear)) & vbCrLf
         outputBlock.Text &= "   Days in each month:" & vbCrLf
         outputBlock.Text &= "      "

         For j = 1 To myCals(i).GetMonthsInYear(iYear)
            outputBlock.Text += String.Format(" {0,-5}", myCals(i).GetDaysInMonth(iYear, j))
         Next j
         outputBlock.Text &= vbCrLf

         iMonth = myCals(i).GetMonth(myDT)
         iDay = myCals(i).GetDayOfMonth(myDT)
         outputBlock.Text += String.Format("   IsLeapDay:   {0}", myCals(i).IsLeapDay(iYear, iMonth, iDay)) & vbCrLf
         outputBlock.Text += String.Format("   IsLeapMonth: {0}", myCals(i).IsLeapMonth(iYear, iMonth)) & vbCrLf
         outputBlock.Text += String.Format("   IsLeapYear:  {0}", myCals(i).IsLeapYear(iYear)) & vbCrLf
      Next
   End Sub 
End Class  
'This code produces the following output.  The results vary depending on the date.
'       
'       System.Globalization.GregorianCalendar, Year: 2002
'          MonthsInYear: 12
'          DaysInYear: 365
'          Days in each month:
'              31    28    31    30    31    30    31    31    30    31    30    31   
'          IsLeapDay:   False
'          IsLeapMonth: False
'          IsLeapYear:  False
'       
'       System.Globalization.HebrewCalendar, Year: 5763
'          MonthsInYear: 13
'          DaysInYear: 385
'          Days in each month:
'              30    30    30    29    30    30    29    30    29    30    29    30    29   
'          IsLeapDay:   False
'          IsLeapMonth: False
'          IsLeapYear:  True
'       
'       System.Globalization.HijriCalendar, Year: 1423
'          MonthsInYear: 12
'          DaysInYear: 355
'          Days in each month:
'              30    29    30    29    30    29    30    29    30    29    30    30   
'          IsLeapDay:   False
'          IsLeapMonth: False
'          IsLeapYear:  True
'       
'       System.Globalization.JapaneseCalendar, Year: 14
'          MonthsInYear: 12
'          DaysInYear: 365
'          Days in each month:
'              31    28    31    30    31    30    31    31    30    31    30    31   
'          IsLeapDay:   False
'          IsLeapMonth: False
'          IsLeapYear:  False
'       
'       System.Globalization.JulianCalendar, Year: 2002
'          MonthsInYear: 12
'          DaysInYear: 365
'          Days in each month:
'              31    28    31    30    31    30    31    31    30    31    30    31   
'          IsLeapDay:   False
'          IsLeapMonth: False
'          IsLeapYear:  False
'       
'       System.Globalization.KoreanCalendar, Year: 4335
'          MonthsInYear: 12
'          DaysInYear: 365
'          Days in each month:
'              31    28    31    30    31    30    31    31    30    31    30    31   
'          IsLeapDay:   False
'          IsLeapMonth: False
'          IsLeapYear:  False
'       
'       System.Globalization.TaiwanCalendar, Year: 91
'          MonthsInYear: 12
'          DaysInYear: 365
'          Days in each month:
'              31    28    31    30    31    30    31    31    30    31    30    31   
'          IsLeapDay:   False
'          IsLeapMonth: False
'          IsLeapYear:  False
'       
'       System.Globalization.ThaiBuddhistCalendar, Year: 2545
'          MonthsInYear: 12
'          DaysInYear: 365
'          Days in each month:
'              31    28    31    30    31    30    31    31    30    31    30    31   
'          IsLeapDay:   False
'          IsLeapMonth: False
'          IsLeapYear:  False

using System;
using System.Globalization;


public class Example
{

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {

      // Creates an instance of every Calendar type.
      Calendar[] myCals = new Calendar[7];
      myCals[0] = new GregorianCalendar();
      myCals[1] = new HebrewCalendar();
      myCals[2] = new HijriCalendar();
      myCals[3] = new JapaneseCalendar();
      myCals[4] = new KoreanCalendar();
      myCals[5] = new TaiwanCalendar();
      myCals[6] = new ThaiBuddhistCalendar();

      // For each calendar, displays the current year, the number of months in that year,
      // and the number of days in each month of that year.
      int i, j, iYear, iMonth, iDay;
      DateTime myDT = DateTime.Today;

      for (i = 0; i < myCals.Length; i++)
      {
         iYear = myCals[i].GetYear(myDT);
         outputBlock.Text += "\n";
         outputBlock.Text += String.Format("{0}, Year: {1}", myCals[i].GetType(), myCals[i].GetYear(myDT)) + "\n";
         outputBlock.Text += String.Format("   MonthsInYear: {0}", myCals[i].GetMonthsInYear(iYear)) + "\n";
         outputBlock.Text += String.Format("   DaysInYear: {0}", myCals[i].GetDaysInYear(iYear)) + "\n";
         outputBlock.Text += "   Days in each month:" + "\n";
         outputBlock.Text += "      ";

         for (j = 1; j <= myCals[i].GetMonthsInYear(iYear); j++)
            outputBlock.Text += String.Format(" {0,-5}", myCals[i].GetDaysInMonth(iYear, j));
         outputBlock.Text += "\n";

         iMonth = myCals[i].GetMonth(myDT);
         iDay = myCals[i].GetDayOfMonth(myDT);
         outputBlock.Text += String.Format("   IsLeapDay:   {0}", myCals[i].IsLeapDay(iYear, iMonth, iDay)) + "\n";
         outputBlock.Text += String.Format("   IsLeapMonth: {0}", myCals[i].IsLeapMonth(iYear, iMonth)) + "\n";
         outputBlock.Text += String.Format("   IsLeapYear:  {0}", myCals[i].IsLeapYear(iYear)) + "\n";

      }

   }

}


/*
This code produces the following output.  The results vary depending on the date.

System.Globalization.GregorianCalendar, Year: 2002
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.HebrewCalendar, Year: 5763
   MonthsInYear: 13
   DaysInYear: 385
   Days in each month:
       30    30    30    29    30    30    29    30    29    30    29    30    29   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.HijriCalendar, Year: 1423
   MonthsInYear: 12
   DaysInYear: 355
   Days in each month:
       30    29    30    29    30    29    30    29    30    29    30    30   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  True

System.Globalization.JapaneseCalendar, Year: 14
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.JulianCalendar, Year: 2002
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.KoreanCalendar, Year: 4335
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.TaiwanCalendar, Year: 91
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

System.Globalization.ThaiBuddhistCalendar, Year: 2545
   MonthsInYear: 12
   DaysInYear: 365
   Days in each month:
       31    28    31    30    31    30    31    31    30    31    30    31   
   IsLeapDay:   False
   IsLeapMonth: False
   IsLeapYear:  False

*/

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.