GregorianCalendar.AddMonths(DateTime, Int32) GregorianCalendar.AddMonths(DateTime, Int32) GregorianCalendar.AddMonths(DateTime, Int32) GregorianCalendar.AddMonths(DateTime, Int32) Method

Definition

Returns a DateTime that is the specified number of months away from the specified DateTime.

public:
 override DateTime AddMonths(DateTime time, int months);
public override DateTime AddMonths (DateTime time, int months);
override this.AddMonths : DateTime * int -> DateTime
Public Overrides Function AddMonths (time As DateTime, months As Integer) As DateTime

Parameters

time
DateTime DateTime DateTime DateTime

The DateTime to which to add months.

months
Int32 Int32 Int32 Int32

The number of months to add.

Returns

The DateTime that results from adding the specified number of months to the specified DateTime.

Exceptions

The resulting DateTime is outside the supported range.

Examples

The following code example displays the values of several components of a DateTime in terms of the Gregorian calendar.

using namespace System;
using namespace System::Globalization;
void DisplayValues( Calendar^ myCal, DateTime myDT )
{
   Console::WriteLine( "   Era:        {0}", myCal->GetEra( myDT ) );
   Console::WriteLine( "   Year:       {0}", myCal->GetYear( myDT ) );
   Console::WriteLine( "   Month:      {0}", myCal->GetMonth( myDT ) );
   Console::WriteLine( "   DayOfYear:  {0}", myCal->GetDayOfYear( myDT ) );
   Console::WriteLine( "   DayOfMonth: {0}", myCal->GetDayOfMonth( myDT ) );
   Console::WriteLine( "   DayOfWeek:  {0}", myCal->GetDayOfWeek( myDT ) );
   Console::WriteLine();
}

int main()
{
   
   // Sets a DateTime to April 3, 2002 of the Gregorian calendar.
   DateTime myDT = DateTime(2002,4,3,gcnew GregorianCalendar);
   
   // Creates an instance of the GregorianCalendar.
   GregorianCalendar^ myCal = gcnew GregorianCalendar;
   
   // Displays the values of the DateTime.
   Console::WriteLine( "April 3, 2002 of the Gregorian calendar:" );
   DisplayValues( myCal, myDT );
   
   // Adds two years and ten months.
   myDT = myCal->AddYears( myDT, 2 );
   myDT = myCal->AddMonths( myDT, 10 );
   
   // Displays the values of the DateTime.
   Console::WriteLine( "After adding two years and ten months:" );
   DisplayValues( myCal, myDT );
}

/*
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

*/
using System;
using System.Globalization;


public class SamplesGregorianCalendar  {

   public static void Main()  {

      // 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.
      Console.WriteLine( "April 3, 2002 of the Gregorian calendar:" );
      DisplayValues( myCal, myDT );

      // Adds two years and ten months.
      myDT = myCal.AddYears( myDT, 2 );
      myDT = myCal.AddMonths( myDT, 10 );

      // Displays the values of the DateTime.
      Console.WriteLine( "After adding two years and ten months:" );
      DisplayValues( myCal, myDT );

   }

   public static void DisplayValues( Calendar myCal, DateTime myDT )  {
      Console.WriteLine( "   Era:        {0}", myCal.GetEra( myDT ) );
      Console.WriteLine( "   Year:       {0}", myCal.GetYear( myDT ) );
      Console.WriteLine( "   Month:      {0}", myCal.GetMonth( myDT ) );
      Console.WriteLine( "   DayOfYear:  {0}", myCal.GetDayOfYear( myDT ) );
      Console.WriteLine( "   DayOfMonth: {0}", myCal.GetDayOfMonth( myDT ) );
      Console.WriteLine( "   DayOfWeek:  {0}", myCal.GetDayOfWeek( myDT ) );
      Console.WriteLine();
   }

}

/*
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

*/
Imports System
Imports System.Globalization


Public Class SamplesGregorianCalendar   

   Public Shared Sub Main()

      ' 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.
      Console.WriteLine("April 3, 2002 of the Gregorian calendar:")
      DisplayValues(myCal, myDT)

      ' Adds two years and ten months.
      myDT = myCal.AddYears(myDT, 2)
      myDT = myCal.AddMonths(myDT, 10)

      ' Displays the values of the DateTime.
      Console.WriteLine("After adding two years and ten months:")
      DisplayValues(myCal, myDT)

   End Sub 'Main

   Public Shared Sub DisplayValues(myCal As Calendar, myDT As DateTime)
      Console.WriteLine("   Era:        {0}", myCal.GetEra(myDT))
      Console.WriteLine("   Year:       {0}", myCal.GetYear(myDT))
      Console.WriteLine("   Month:      {0}", myCal.GetMonth(myDT))
      Console.WriteLine("   DayOfYear:  {0}", myCal.GetDayOfYear(myDT))
      Console.WriteLine("   DayOfMonth: {0}", myCal.GetDayOfMonth(myDT))
      Console.WriteLine("   DayOfWeek:  {0}", myCal.GetDayOfWeek(myDT))
      Console.WriteLine()
   End Sub 'DisplayValues

End Class 'SamplesGregorianCalendar 


'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


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)

Applies to

See also