DateTime.Add() Method in C#

Last Updated : 18 Jan, 2019

This method is used to return a new DateTime that adds the value of the specified TimeSpan to the value of this instance.

Syntax:

public DateTime Add (TimeSpan value);

Here, value is a positive or negative time interval.

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

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

Below programs illustrate the use of DateTime.Add(TimeSpan) Method:

Example 1:

// C# program to demonstrate the 
// DateTime.Add(TimeSpan) 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, 
                                           8, 0, 15); 
  
            // creating object of TimeSpan 
            TimeSpan duration = new TimeSpan(36, 0, 0, 0); 
  
            // adding the TimeSpan of 36 days 
            // using Add() method; 
            DateTime date2 = date1.Add(duration); 
  
            // Display the date1 
            System.Console.WriteLine("DateTime before "+ 
                      "operation: {0:y} {0:dd}", date1); 
  
            // Display the date2 
            System.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: 2010 February 06

Example 2: For ArgumentOutOfRangeException

// C# program to demonstrate the 
// DateTime.Add(TimeSpan) 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.MinValue; 
  
            // Display the date1 
            Console.WriteLine("DateTime before "+ 
               "operation: {0:y} {0:dd}", date1); 
  
            // creating object of TimeSpan 
            TimeSpan duration = new TimeSpan(-36, 0, 0, 0); 
  
            // adding the TimeSpan of 36 days 
            // using Add() method; 
            DateTime date2 = date1.Add(duration); 
  
            // Display the date2 
            Console.WriteLine("\nDateTime after"+ 
              " operation: {0:y} {0:dd}", date2); 
        } 
  
        catch (ArgumentOutOfRangeException e) 
       { 
            Console.WriteLine("\nThe resulting DateTime"+ 
                          " is less than the MinValue "); 
            Console.Write("Exception Thrown: "); 
            Console.Write("{0}", e.GetType(), e.Message); 
        } 
    } 
} 

Output:

DateTime before operation: 0001 January 01

The resulting DateTime is less than the MinValue 
Exception Thrown: System.ArgumentOutOfRangeException

Note:

The Add method takes into account leap years and the number of days in a month when performing date arithmetic.
This method does not change the value of this DateTime. Instead, it returns a new DateTime whose value is the result of this operation.

Reference: