DateTime.AddYears() Method in C#

This method is used to returns a new DateTime that adds the specified number of years to the value of this instance.

Syntax:

public DateTime AddYears (int value);

Here, the value is the number of years. The value parameter can be negative or positive.

Return Value: This method returns an object whose value is the sum of the date and time represented by this instance and the number of years represented by value.

Exception: This method will give ArgumentOutOfRangeException if the resulting DateTime is less than MinValue or greater than MaxValue.

Below programs illustrate the use of DateTime.AddYears(Int32) Method:

Example 1:

// C# program to demonstrate the
// DateTime.AddYears(Int32) Method
using System;
using System.Globalization;

class GFG {

// Main Method
public static void Main()
{

    try {

        // creating object of DateTime
        DateTime date1 = new DateTime(2010, 1, 1,
                                        4, 0, 15);

        // adding the 8 Months
        // using AddYears() method;
        DateTime date2 = date1.AddYears(8);

        // Display the date1
        Console.WriteLine("DateTime before operation: "
                              + "{0:y} {0:dd}", date1);

        // Display the date2
        Console.WriteLine("\nDateTime after operation: "
                              + "{0:y} {0:dd}", date2);

    }

    catch (ArgumentOutOfRangeException e)
    {
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }
}
}

Output:

DateTime before operation: 2010 January 01

DateTime after operation: 2018 January 01

Example 2: For ArgumentOutOfRangeException

// C# program to demonstrate the
// DateTime.AddYears(Int32) Method
using System;
using System.Globalization;

class GFG {

    // Main Method
    public static void Main()
    {
        try {

            // creating object of DateTime
            // and initialize with MinValue
            DateTime date1 = DateTime.MaxValue;

            // Display the date1
            Console.WriteLine("DateTime before operation: "
                                  + "{0:y} {0:dd}", date1);


            // adding the TimeSpan of 8 Years
            // using AddYears() method;
            DateTime date2 = date1.AddYears(5);

            // Display the date2
            Console.WriteLine("DateTime before operation: "
                                  + "{0:y} {0:dd}", date2);

        }

        catch (ArgumentOutOfRangeException e)
        {
            Console.WriteLine("\nThe resulting DateTime is "+
                      "greater than the DateTime.MaxValue ");

            Console.Write("Exception Thrown: ");
            Console.Write("{0}", e.GetType(), e.Message);
        }
    }
}

Output:

DateTime before operation: 9999 December 31

The resulting DateTime is greater than the DateTime.MaxValue 
Exception Thrown: System.ArgumentOutOfRangeException

Note:

• This method does not change the value of this DateTime object. Instead, it returns a new DateTime object whose value is the result of this operation.
• This method calculates the resulting year taking into account leap years. The month and time-of-day part of the resulting DateTime object remains the same as this instance.
• If the current instance represents the leap day in a leap year, the return value depends on the target date:
  • If value + DateTime.Year is also a leap year, the return value represents the leap day in that year. For example, if four years is added to February 29, 2016, the date returned is February 29, 2020.
  • If value + DateTime.Year is not a leap year, the return value represents the day before the leap day in that year. For example, if one year is added to February 29, 2016, the date returned is February 28, 2017.

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.datetime.addyears?view=netframework-4.7.2