DateTime.AddDays Method (Double)
Returns a new DateTime that adds the specified number of days to the value of this instance.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- value
-
Type:
System.Double
A number of whole and fractional days. The value parameter can be negative or positive.
Return Value
Type: System.DateTimeAn object whose value is the sum of the date and time represented by this instance and the number of days represented by value.
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException |
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 valueis the fractional part of a day. For example, 4.5 is equivalent to 4 days, 12 hours, 0 minutes, 0 seconds, 0 milliseconds, and 0 ticks.
The value parameter is rounded to the nearest millisecond.
TheAddDays method takes into account leap years and the number of days in a month when performing date arithmetic.
The following example uses the AddDays method to determine the day of the week 36 days after the current date.
using System; class Class1 { static void Main() { DateTime today = DateTime.Now; DateTime answer = today.AddDays(36); Console.WriteLine("Today: {0:dddd}", today); Console.WriteLine("36 days from today: {0:dddd}", answer); } } // The example displays output like the following: // Today: Wednesday // 36 days from today: Thursday
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1