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GregorianCalendar.IsLeapDay Method (Int32, Int32, Int32, Int32)

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

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

Syntax

'Declaration
Public Overrides Function IsLeapDay ( _
    year As Integer, _
    month As Integer, _
    day As Integer, _
    era As Integer _
) As Boolean

public override bool IsLeapDay(
    int year,
    int month,
    int day,
    int era
)

Parameters

  • year
    Type: System.Int32
    An integer that represents the year.
  • month
    Type: System.Int32
    An integer from 1 to 12 that represents the month.
  • day
    Type: System.Int32
    An integer from 1 to 31 that represents the day.
  • era
    Type: System.Int32
    An integer that represents the era.

Return Value

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

Exceptions

Exception Condition
ArgumentOutOfRangeException

era is outside the range supported by the calendar.

-or-

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.

Remarks

A leap year in the Gregorian calendar is defined as a year that is evenly divisible by four, except if it is divisible by 100. However, years that are divisible by 400 are leap years. For example, the year 1900 was not a leap year, but the year 2000 was. A common year has 365 days and a leap year has 366 days.

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

Examples

The following code example calls IsLeapDay for the last day of the second month (February) for five years in each of the eras.

Imports System.Globalization

Public Class Example
   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      ' Creates and initializes a GregorianCalendar.
      Dim myCal As New GregorianCalendar()

      ' Creates a holder for the last day of the second month (February).
      Dim iLastDay As Integer

      ' Displays the header.
      outputBlock.Text &= "YEAR" + ControlChars.Tab
      Dim y As Integer
      For y = 2001 To 2005
         outputBlock.Text += String.Format(ControlChars.Tab + "{0}", y)
      Next 
      outputBlock.Text &= vbCrLf

      ' Checks five years in the current era.
      outputBlock.Text &= "CurrentEra:"
      For y = 2001 To 2005
         iLastDay = myCal.GetDaysInMonth(y, 2, GregorianCalendar.CurrentEra)
         outputBlock.Text += String.Format(ControlChars.Tab + "{0}", myCal.IsLeapDay(y, 2, iLastDay, GregorianCalendar.CurrentEra))
      Next 
      outputBlock.Text &= vbCrLf

      ' Checks five years in each of the eras.
      For i As Integer = 0 To myCal.Eras.Length - 1
         outputBlock.Text += String.Format("Era {0}:" + ControlChars.Tab, myCal.Eras(i))
         For y = 2001 To 2005
            iLastDay = myCal.GetDaysInMonth(y, 2, myCal.Eras(i))
            outputBlock.Text += String.Format(ControlChars.Tab + "{0}", myCal.IsLeapDay(y, 2, iLastDay, myCal.Eras(i)))
         Next 
         outputBlock.Text &= vbCrLf
      Next 
   End Sub 
End Class 
' This example produces the following output.
'       YEAR            2001    2002    2003    2004    2005
'       CurrentEra:     False   False   False   True    False
'       Era 1:          False   False   False   True    False

using System;
using System.Globalization;


public class Example
{

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

      // Creates and initializes a GregorianCalendar.
      GregorianCalendar myCal = new GregorianCalendar();

      // Creates a holder for the last day of the second month (February).
      int iLastDay;

      // Displays the header.
      outputBlock.Text += "YEAR\t";
      for (int y = 2001; y <= 2005; y++)
         outputBlock.Text += String.Format("\t{0}", y);
      outputBlock.Text += "\n";

      // Checks five years in the current era.
      outputBlock.Text += "CurrentEra:";
      for (int y = 2001; y <= 2005; y++)
      {
         iLastDay = myCal.GetDaysInMonth(y, 2, GregorianCalendar.CurrentEra);
         outputBlock.Text += String.Format("\t{0}", myCal.IsLeapDay(y, 2, iLastDay, GregorianCalendar.CurrentEra));
      }
      outputBlock.Text += "\n";

      // Checks five years in each of the eras.
      for (int i = 0; i < myCal.Eras.Length; i++)
      {
         outputBlock.Text += String.Format("Era {0}:\t", myCal.Eras[i]);
         for (int y = 2001; y <= 2005; y++)
         {
            iLastDay = myCal.GetDaysInMonth(y, 2, myCal.Eras[i]);
            outputBlock.Text += String.Format("\t{0}", myCal.IsLeapDay(y, 2, iLastDay, myCal.Eras[i]));
         }
         outputBlock.Text += "\n";
      }

   }

}

/*
This code produces the following output.

YEAR            2001    2002    2003    2004    2005
CurrentEra:     False   False   False   True    False
Era 1:          False   False   False   True    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.