• Article

DateTime.IsLeapYear Method

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Returns an indication whether the specified year is a leap year.

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

Syntax

'Declaration
Public Shared Function IsLeapYear ( _
    year As Integer _
) As Boolean

public static bool IsLeapYear(
    int year
)

Parameters

Return Value

Type: System.Boolean
true if year is a leap year; otherwise, false.

Exceptions

Exception Condition
ArgumentOutOfRangeException

year is less than 1 or greater than 9999.

Remarks

year is specified as a 4-digit base 10 number; for example, 1996.

year is always interpreted as a year in the Gregorian calendar. To determine whether a particular year was a leap year in some other calendar, call that calendar object's IsLeapYear method.

Examples

The following example uses the IsLeapYear method to determine which years between 1994 and 2014 are leap years. The example also illustrates the result when the AddYears method is used to add a year to a leap day.

Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      For year As Integer = 1994 To 2014
         If DateTime.IsLeapYear(year) Then
            outputBlock.Text += String.Format("{0} is a leap year.", year) & vbCrLf
            Dim leapDay As New Date(year, 2, 29)
            Dim nextYear As Date = leapDay.AddYears(1)
            outputBlock.Text += String.Format("   One year from {0} is {1}.", _
                              leapDay.ToString("d"), _
                              nextYear.ToString("d")) & vbCrLf
         End If
      Next
   End Sub
End Module
' The example displays the following output:
'       1996 is a leap year.
'          One year from 2/29/1996 is 2/28/1997.
'       2000 is a leap year.
'          One year from 2/29/2000 is 2/28/2001.
'       2004 is a leap year.
'          One year from 2/29/2004 is 2/28/2005.
'       2008 is a leap year.
'          One year from 2/29/2008 is 2/28/2009.
'       2012 is a leap year.
'          One year from 2/29/2012 is 2/28/2013.

using System;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      for (int year = 1994; year <= 2014; year++)
      {
         if (DateTime.IsLeapYear(year))
         {
            outputBlock.Text += String.Format("{0} is a leap year.", year) + "\n";
            DateTime leapDay = new DateTime(year, 2, 29);
            DateTime nextYear = leapDay.AddYears(1);
            outputBlock.Text += String.Format("   One year from {0} is {1}.",
                              leapDay.ToString("d"),
                              nextYear.ToString("d")) + "\n";
         }
      }
   }
}
// The example produces the following output:
//       1996 is a leap year.
//          One year from 2/29/1996 is 2/28/1997.
//       2000 is a leap year.
//          One year from 2/29/2000 is 2/28/2001.
//       2004 is a leap year.
//          One year from 2/29/2004 is 2/28/2005.
//       2008 is a leap year.
//          One year from 2/29/2008 is 2/28/2009.
//       2012 is a leap year.
//          One year from 2/29/2012 is 2/28/2013.

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.