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Calendar.IsLeapDay Method (Int32, Int32, Int32)

April 12, 2014

Determines whether the specified date in the current era is a leap day.

Namespace:  System.Globalization
Assembly:  mscorlib (in mscorlib.dll)
public virtual bool IsLeapDay(
	int year,
	int month,
	int day
)

Parameters

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

Return Value

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

year is outside the range supported by the calendar.

-or-

month is outside the range supported by the calendar.

-or-

day is outside the range supported by the calendar.

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 day is a day that occurs only in a leap year. For example, in the Gregorian calendar, the 29th day of February is the only leap day.

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


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

*/


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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