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DateTime.DayOfYear Property

Gets the day of the year represented by this instance.

Namespace:  System
Assemblies:   mscorlib (in mscorlib.dll)
  System.Runtime (in System.Runtime.dll)

public int DayOfYear { get; }

Property Value

Type: System.Int32
The day of the year, expressed as a value between 1 and 366.

The DayOfYear property takes leap years into account when it calculates the day of the year. The property value always reflects the day of the year in the Gregorian calendar, regardless of the current thread culture's current calendar. To retrieve the day of the year in a different calendar, call the Calendar.GetDayOfYear method of that calendar.

The following example displays the day of the year of December 31 for the years 2010-2020 in the Gregorian calendar. Note that the example shows that December 31 is the 366th day of the year in leap years.

using System;

public class Example
{
   public static void Main()
   {
      DateTime dec31 = new DateTime(2010, 12, 31);
      for (int ctr = 0; ctr <= 10; ctr++) {
         DateTime dateToDisplay = dec31.AddYears(ctr);
         Console.WriteLine("{0:d}: day {1} of {2} {3}", dateToDisplay, 
                           dateToDisplay.DayOfYear,
                           dateToDisplay.Year,   
                           DateTime.IsLeapYear(dateToDisplay.Year) ? 
                                               "(Leap Year)" : ""); 
      }  

   }
}
// The example displays the following output: 
//       12/31/2010: day 365 of 2010 
//       12/31/2011: day 365 of 2011 
//       12/31/2012: day 366 of 2012 (Leap Year) 
//       12/31/2013: day 365 of 2013 
//       12/31/2014: day 365 of 2014 
//       12/31/2015: day 365 of 2015 
//       12/31/2016: day 366 of 2016 (Leap Year) 
//       12/31/2017: day 365 of 2017 
//       12/31/2018: day 365 of 2018 
//       12/31/2019: day 365 of 2019 
//       12/31/2020: day 366 of 2020 (Leap Year)

.NET Framework

Supported in: 4.5.3, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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