DateTime.AddSeconds Method (Double)


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Returns a new DateTime that adds the specified number of seconds to the value of this instance.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

public DateTime AddSeconds(
	double value


Type: System.Double

A number of whole and fractional seconds. The value parameter can be negative or positive.

Return Value

Type: System.DateTime

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 Condition

The resulting DateTime is less than MinValue or greater than MaxValue.

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 value is the fractional part of a second. For example, 4.5 is equivalent to 4 seconds, 500 milliseconds, and 0 ticks.

The value parameter is rounded to the nearest millisecond.

The following example uses theAddSecondsmethod to add 30 seconds and the number of seconds in one day to a DateTime value. It then displays each new value and displays the difference between it and the original value. The difference is displayed both as a time span and as a number of ticks.

using System;

public class Example
   public static void Main()
      string dateFormat = "MM/dd/yyyy hh:mm:ss";
      DateTime date1 = new DateTime(2014, 9, 8, 16, 0, 0);
      Console.WriteLine("Original date: {0} ({1:N0} ticks)\n",
                        date1.ToString(dateFormat), date1.Ticks);

      DateTime date2 = date1.AddSeconds(30);
      Console.WriteLine("Second date:   {0} ({1:N0} ticks)",
                        date2.ToString(dateFormat), date2.Ticks);
      Console.WriteLine("Difference between dates: {0} ({1:N0} ticks)\n",
                        date2 - date1, date2.Ticks - date1.Ticks);                        

      // Add 1 day's worth of seconds (60 secs. * 60 mins * 24 hrs.
      DateTime date3 = date1.AddSeconds(60 * 60 * 24);
      Console.WriteLine("Third date:    {0} ({1:N0} ticks)",
                        date3.ToString(dateFormat), date3.Ticks);
      Console.WriteLine("Difference between dates: {0} ({1:N0} ticks)",
                        date3 - date1, date3.Ticks - date1.Ticks);                        
// The example displays the following output:
//    Original date: 09/08/2014 04:00:00 (635,457,888,000,000,000 ticks)
//    Second date:   09/08/2014 04:00:30 (635,457,888,300,000,000 ticks)
//    Difference between dates: 00:00:30 (300,000,000 ticks)
//    Third date:    09/09/2014 04:00:00 (635,458,752,000,000,000 ticks)
//    Difference between dates: 1.00:00:00 (864,000,000,000 ticks)

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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