Calendar.AddWeeks(DateTime, Int32) Method
Definition
Important
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public:
virtual DateTime AddWeeks(DateTime time, int weeks);public virtual DateTime AddWeeks (DateTime time, int weeks);abstract member AddWeeks : DateTime * int -> DateTime
override this.AddWeeks : DateTime * int -> DateTimePublic Overridable Function AddWeeks (time As DateTime, weeks As Integer) As DateTimeParameters
- weeks
- Int32
The number of weeks to add.
Returns
The DateTime that results from adding the specified number of weeks to the specified DateTime.
Exceptions
The resulting DateTime is outside the supported range of this calendar.
weeks is outside the supported range of the DateTime return value.
Examples
The following code example demonstrates the members of the Calendar class.
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( " Hour: {0}", myCal->GetHour( myDT ) );
Console::WriteLine( " Minute: {0}", myCal->GetMinute( myDT ) );
Console::WriteLine( " Second: {0}", myCal->GetSecond( myDT ) );
Console::WriteLine( " Milliseconds: {0}", myCal->GetMilliseconds( myDT ) );
Console::WriteLine();
}
int main()
{
// Sets a DateTime to April 3, 2002 of the Gregorian calendar.
DateTime myDT = DateTime(2002,4,3,gcnew GregorianCalendar);
// Uses the default calendar of the InvariantCulture.
Calendar^ myCal = CultureInfo::InvariantCulture->Calendar;
// Displays the values of the DateTime.
Console::WriteLine( "April 3, 2002 of the Gregorian calendar:" );
DisplayValues( myCal, myDT );
// Adds 5 to every component of the DateTime.
myDT = myCal->AddYears( myDT, 5 );
myDT = myCal->AddMonths( myDT, 5 );
myDT = myCal->AddWeeks( myDT, 5 );
myDT = myCal->AddDays( myDT, 5 );
myDT = myCal->AddHours( myDT, 5 );
myDT = myCal->AddMinutes( myDT, 5 );
myDT = myCal->AddSeconds( myDT, 5 );
myDT = myCal->AddMilliseconds( myDT, 5 );
// Displays the values of the DateTime.
Console::WriteLine( "After adding 5 to each component of the DateTime:" );
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
Hour: 0
Minute: 0
Second: 0
Milliseconds: 0
After adding 5 to each component of the DateTime:
Era: 1
Year: 2007
Month: 10
DayOfYear: 286
DayOfMonth: 13
DayOfWeek: Saturday
Hour: 5
Minute: 5
Second: 5
Milliseconds: 5
*/
using System;
using System.Globalization;
public class SamplesCalendar {
public static void Main() {
// Sets a DateTime to April 3, 2002 of the Gregorian calendar.
DateTime myDT = new DateTime( 2002, 4, 3, new GregorianCalendar() );
// Uses the default calendar of the InvariantCulture.
Calendar myCal = CultureInfo.InvariantCulture.Calendar;
// Displays the values of the DateTime.
Console.WriteLine( "April 3, 2002 of the Gregorian calendar:" );
DisplayValues( myCal, myDT );
// Adds 5 to every component of the DateTime.
myDT = myCal.AddYears( myDT, 5 );
myDT = myCal.AddMonths( myDT, 5 );
myDT = myCal.AddWeeks( myDT, 5 );
myDT = myCal.AddDays( myDT, 5 );
myDT = myCal.AddHours( myDT, 5 );
myDT = myCal.AddMinutes( myDT, 5 );
myDT = myCal.AddSeconds( myDT, 5 );
myDT = myCal.AddMilliseconds( myDT, 5 );
// Displays the values of the DateTime.
Console.WriteLine( "After adding 5 to each component of the DateTime:" );
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( " Hour: {0}", myCal.GetHour( myDT ) );
Console.WriteLine( " Minute: {0}", myCal.GetMinute( myDT ) );
Console.WriteLine( " Second: {0}", myCal.GetSecond( myDT ) );
Console.WriteLine( " Milliseconds: {0}", myCal.GetMilliseconds( 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
Hour: 0
Minute: 0
Second: 0
Milliseconds: 0
After adding 5 to each component of the DateTime:
Era: 1
Year: 2007
Month: 10
DayOfYear: 286
DayOfMonth: 13
DayOfWeek: Saturday
Hour: 5
Minute: 5
Second: 5
Milliseconds: 5
*/
Imports System.Globalization
Public Class SamplesCalendar
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())
' Uses the default calendar of the InvariantCulture.
Dim myCal As Calendar = CultureInfo.InvariantCulture.Calendar
' Displays the values of the DateTime.
Console.WriteLine("April 3, 2002 of the Gregorian calendar:")
DisplayValues(myCal, myDT)
' Adds 5 to every component of the DateTime.
myDT = myCal.AddYears(myDT, 5)
myDT = myCal.AddMonths(myDT, 5)
myDT = myCal.AddWeeks(myDT, 5)
myDT = myCal.AddDays(myDT, 5)
myDT = myCal.AddHours(myDT, 5)
myDT = myCal.AddMinutes(myDT, 5)
myDT = myCal.AddSeconds(myDT, 5)
myDT = myCal.AddMilliseconds(myDT, 5)
' Displays the values of the DateTime.
Console.WriteLine("After adding 5 to each component of the DateTime:")
DisplayValues(myCal, myDT)
End Sub
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(" Hour: {0}", myCal.GetHour(myDT))
Console.WriteLine(" Minute: {0}", myCal.GetMinute(myDT))
Console.WriteLine(" Second: {0}", myCal.GetSecond(myDT))
Console.WriteLine(" Milliseconds: {0}", myCal.GetMilliseconds(myDT))
Console.WriteLine()
End Sub
End Class
'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
' Hour: 0
' Minute: 0
' Second: 0
' Milliseconds: 0
'
'After adding 5 to each component of the DateTime:
' Era: 1
' Year: 2007
' Month: 10
' DayOfYear: 286
' DayOfMonth: 13
' DayOfWeek: Saturday
' Hour: 5
' Minute: 5
' Second: 5
' Milliseconds: 5
Remarks
The weeks value is added to the specified DateTime. If weeks is negative, the resulting DateTime is earlier than the specified DateTime.
The month part of the resulting DateTime is affected if the resulting day is outside the month of the specified DateTime. The year part of the resulting DateTime is affected if the resulting month is outside the year of the specified DateTime. The era part of the resulting DateTime is affected 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.
In all .NET classes derived from the Calendar class, a week is defined as seven days.
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.AddWeeks(time, weeks), time.Kind);
returnTime = DateTime.SpecifyKind(cal.AddWeeks(time, weeks), time.Kind)
Applies to
See also
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