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DateTime.DayOfYear Property

Gets the day of the year represented by this instance.

Namespace:  System
Assembly:  mscorlib (in mscorlib.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: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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