GregorianCalendar.AddMonths Method
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Namespace: System.Globalization
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Overrides Function AddMonths ( _
time As DateTime, _
months As Integer _
) As DateTime
public override DateTime AddMonths(
DateTime time,
int months
)
Parameters
- time
Type: System.DateTime
The DateTime to which to add months.
- months
Type: System.Int32
The number of months to add.
Return Value
Type: System.DateTime
The DateTime that results from adding the specified number of months to the specified DateTime.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentException | The resulting DateTime is outside the supported range. |
| ArgumentOutOfRangeException | months is less than -120000. -or- months is greater than 120000. |
Remarks
The day part of the resulting DateTime is affected if the resulting day is not a valid day in the resulting month of the resulting year. It is changed to the last valid day in the resulting month of the resulting year. The year part of the resulting DateTime is affected if the resulting month is outside the year of the specified DateTime. This implementation supports only the current era. Therefore, ArgumentException is thrown if the resulting year is outside the era of the specified DateTime. The time-of-day part of the resulting DateTime remains the same as the specified DateTime.
For example, if the specified month is October, which has 31 days, the specified day is the 31st day of that month, and the value of the months parameter is 6, the resulting year is one more than the specified year, the resulting month is April, and the resulting day is the 30th day, which is the last day in April.
If the value of the months parameter is negative, the resulting DateTime is earlier than the specified DateTime.
The Kind property of the returned DateTime value always equals DateTimeKind.Unspecified. You can preserve the Kind property of the time parameter by calling the DateTime.SpecifyKind method, as the following example shows.
returnTime = DateTime.SpecifyKind(cal.AddMonths(time, months), time.Kind)
returnTime = DateTime.SpecifyKind(cal.AddMonths(time, months), time.Kind);
Examples
The following code example displays the values of several components of a DateTime in terms of the Gregorian calendar.
Imports System.Globalization
Public Class Example
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
' Sets a DateTime to April 3, 2002 of the Gregorian calendar.
Dim myDT As New DateTime(2002, 4, 3, New GregorianCalendar())
' Creates an instance of the GregorianCalendar.
Dim myCal As New GregorianCalendar()
' Displays the values of the DateTime.
outputBlock.Text += String.Format("April 3, 2002 of the Gregorian calendar:") & vbCrLf
DisplayValues(outputBlock, myCal, myDT)
' Adds two years and ten months.
myDT = myCal.AddYears(myDT, 2)
myDT = myCal.AddMonths(myDT, 10)
' Displays the values of the DateTime.
outputBlock.Text &= "After adding two years and ten months:" & vbCrLf
DisplayValues(outputBlock, myCal, myDT)
End Sub
Public Shared Sub DisplayValues(ByVal outputBlock As System.Windows.Controls.TextBlock, _
ByVal myCal As Calendar, ByVal myDT As DateTime)
outputBlock.Text += String.Format(" Era: {0}", myCal.GetEra(myDT)) & vbCrLf
outputBlock.Text += String.Format(" Year: {0}", myCal.GetYear(myDT)) & vbCrLf
outputBlock.Text += String.Format(" Month: {0}", myCal.GetMonth(myDT)) & vbCrLf
outputBlock.Text += String.Format(" DayOfYear: {0}", myCal.GetDayOfYear(myDT)) & vbCrLf
outputBlock.Text += String.Format(" DayOfMonth: {0}", myCal.GetDayOfMonth(myDT)) & vbCrLf
outputBlock.Text += String.Format(" DayOfWeek: {0}", myCal.GetDayOfWeek(myDT)) & vbCrLf
outputBlock.Text &= vbCrLf
End Sub
End Class
' This example produces the following output.
' April 3, 2002 of the Gregorian calendar:
' Era: 1
' Year: 2002
' Month: 4
' DayOfYear: 93
' DayOfMonth: 3
' DayOfWeek: Wednesday
'
' After adding two years and ten months:
' Era: 1
' Year: 2005
' Month: 2
' DayOfYear: 34
' DayOfMonth: 3
' DayOfWeek: Thursday
using System;
using System.Globalization;
public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
// Sets a DateTime to April 3, 2002 of the Gregorian calendar.
DateTime myDT = new DateTime(2002, 4, 3, new GregorianCalendar());
// Creates an instance of the GregorianCalendar.
GregorianCalendar myCal = new GregorianCalendar();
// Displays the values of the DateTime.
outputBlock.Text += String.Format("April 3, 2002 of the Gregorian calendar:") + "\n";
DisplayValues(outputBlock, myCal, myDT);
// Adds two years and ten months.
myDT = myCal.AddYears(myDT, 2);
myDT = myCal.AddMonths(myDT, 10);
// Displays the values of the DateTime.
outputBlock.Text += "After adding two years and ten months:" + "\n";
DisplayValues(outputBlock, myCal, myDT);
}
public static void DisplayValues(System.Windows.Controls.TextBlock outputBlock, Calendar myCal, DateTime myDT)
{
outputBlock.Text += String.Format(" Era: {0}", myCal.GetEra(myDT)) + "\n";
outputBlock.Text += String.Format(" Year: {0}", myCal.GetYear(myDT)) + "\n";
outputBlock.Text += String.Format(" Month: {0}", myCal.GetMonth(myDT)) + "\n";
outputBlock.Text += String.Format(" DayOfYear: {0}", myCal.GetDayOfYear(myDT)) + "\n";
outputBlock.Text += String.Format(" DayOfMonth: {0}", myCal.GetDayOfMonth(myDT)) + "\n";
outputBlock.Text += String.Format(" DayOfWeek: {0}", myCal.GetDayOfWeek(myDT)) + "\n";
outputBlock.Text += "\n";
}
}
/*
This code produces the following output.
April 3, 2002 of the Gregorian calendar:
Era: 1
Year: 2002
Month: 4
DayOfYear: 93
DayOfMonth: 3
DayOfWeek: Wednesday
After adding two years and ten months:
Era: 1
Year: 2005
Month: 2
DayOfYear: 34
DayOfMonth: 3
DayOfWeek: Thursday
*/
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.