DateTime.AddSeconds() Method in C#

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

Syntax:

public DateTime AddSeconds (double value);

Here, value is a number of whole and fractional seconds. 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 seconds represented by value.

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

Below programs illustrate the use of the above-discussed method:

Example 1:

// C# program to demonstrate the
// DateTime.AddSeconds(Double) Method
using System;

class GFG {

// Main Method
public static void Main()
{

    // defining the format of date
    string dateFormat = "MM/dd/yyyy hh:mm:ss";

    // Creating a DateTime object and
    // taking a particular date and time
    DateTime d1 = new DateTime(2018, 9, 7, 7, 0, 0);

    Console.WriteLine("Original date: {0}",
                  d1.ToString(dateFormat));

    // Taking seconds
    int sec = 30;

    // using method
    DateTime d2 = d1.AddSeconds(sec);

    Console.WriteLine("After Using Method: {0}",
                    d2.ToString(dateFormat));
}
}

Output:

Original date: 09/07/2018 07:00:00
After Using Method: 09/07/2018 07:00:30

Example 2:

// C# program to demonstrate the
// DateTime.AddSeconds(Double) Method
using System;

class GFG {

// Main Method
public static void Main()
{

    // defining the format of date
    string dateFormat = "MM/dd/yyyy hh:mm:ss";

    // Creating a DateTime object and
    // taking a MaxValue of Date
    DateTime d1 = DateTime.MaxValue;

    Console.WriteLine("Original date: {0}",
                  d1.ToString(dateFormat));

    // Taking seconds
    int sec = 17;

    // using method will give error as the
    // resulting DateTime will be greater
    // than the MaxValue
    DateTime d2 = d1.AddSeconds(sec);

    Console.WriteLine("After Using Method: {0}",
                      d2.ToString(dateFormat));
}
}

Runtime Error:

Unhandled Exception:
System.ArgumentOutOfRangeException: The added or subtracted value results in an un-representable DateTime.
Parameter name: value

Note:

• This method does not change the value of this DateTime. Instead, it returns a new DateTime whose value is the result of this operation.
• The fractional part of the value is the fractional part of a minute. For example, 7.5 is equivalent to 7 minutes, 30 seconds, 0 milliseconds, and 0 ticks.
• The value parameter is rounded to the nearest millisecond.

Reference:

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