Articolo
11/18/2011

Calendar Class

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Represents time in divisions, such as weeks, months, and years.

Inheritance Hierarchy

System.Object
  System.Globalization.Calendar
    System.Globalization.GregorianCalendar
    System.Globalization.HebrewCalendar
    System.Globalization.HijriCalendar
    System.Globalization.JapaneseCalendar
    System.Globalization.KoreanCalendar
    System.Globalization.PersianCalendar
    System.Globalization.TaiwanCalendar
    System.Globalization.ThaiBuddhistCalendar
    System.Globalization.UmAlQuraCalendar

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

Syntax

'Declaration
<ComVisibleAttribute(True)> _
Public MustInherit Class Calendar

[ComVisibleAttribute(true)]
public abstract class Calendar

The Calendar type exposes the following members.

Constructors

	Name	Description
	Calendar	Initializes a new instance of the Calendar class.

Top

Properties

	Name	Description
	Eras	When overridden in a derived class, gets the list of eras in the current calendar.
	IsReadOnly	Gets a value indicating whether this Calendar object is read-only.
	MaxSupportedDateTime	Gets the latest date and time supported by this Calendar object.
	MinSupportedDateTime	Gets the earliest date and time supported by this Calendar object.
	TwoDigitYearMax	Gets or sets the last year of a 100-year range that can be represented by a 2-digit year.

Top

Methods

	Name	Description
	AddDays	Returns a DateTime that is the specified number of days away from the specified DateTime.
	AddHours	Returns a DateTime that is the specified number of hours away from the specified DateTime.
	AddMilliseconds	Returns a DateTime that is the specified number of milliseconds away from the specified DateTime.
	AddMinutes	Returns a DateTime that is the specified number of minutes away from the specified DateTime.
	AddMonths	When overridden in a derived class, returns a DateTime that is the specified number of months away from the specified DateTime.
	AddSeconds	Returns a DateTime that is the specified number of seconds away from the specified DateTime.
	AddWeeks	Returns a DateTime that is the specified number of weeks away from the specified DateTime.
	AddYears	When overridden in a derived class, returns a DateTime that is the specified number of years away from the specified DateTime.
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetDayOfMonth	When overridden in a derived class, returns the day of the month in the specified DateTime.
	GetDayOfWeek	When overridden in a derived class, returns the day of the week in the specified DateTime.
	GetDayOfYear	When overridden in a derived class, returns the day of the year in the specified DateTime.
	GetDaysInMonth(Int32, Int32)	Returns the number of days in the specified month and year of the current era.
	GetDaysInMonth(Int32, Int32, Int32)	When overridden in a derived class, returns the number of days in the specified month, year, and era.
	GetDaysInYear(Int32)	Returns the number of days in the specified year of the current era.
	GetDaysInYear(Int32, Int32)	When overridden in a derived class, returns the number of days in the specified year and era.
	GetEra	When overridden in a derived class, returns the era in the specified DateTime.
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetHour	Returns the hours value in the specified DateTime.
	GetLeapMonth	Calculates the leap month for a specified year and era.
	GetMilliseconds	Returns the milliseconds value in the specified DateTime.
	GetMinute	Returns the minutes value in the specified DateTime.
	GetMonth	When overridden in a derived class, returns the month in the specified DateTime.
	GetMonthsInYear(Int32)	Returns the number of months in the specified year in the current era.
	GetMonthsInYear(Int32, Int32)	When overridden in a derived class, returns the number of months in the specified year in the specified era.
	GetSecond	Returns the seconds value in the specified DateTime.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetWeekOfYear	Returns the week of the year that includes the date in the specified DateTime value.
	GetYear	When overridden in a derived class, returns the year in the specified DateTime.
	IsLeapDay(Int32, Int32, Int32)	Determines whether the specified date in the current era is a leap day.
	IsLeapDay(Int32, Int32, Int32, Int32)	When overridden in a derived class, determines whether the specified date in the specified era is a leap day.
	IsLeapMonth(Int32, Int32)	Determines whether the specified month in the specified year in the current era is a leap month.
	IsLeapMonth(Int32, Int32, Int32)	When overridden in a derived class, determines whether the specified month in the specified year in the specified era is a leap month.
	IsLeapYear(Int32)	Determines whether the specified year in the current era is a leap year.
	IsLeapYear(Int32, Int32)	When overridden in a derived class, determines whether the specified year in the specified era is a leap year.
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToDateTime(Int32, Int32, Int32, Int32, Int32, Int32, Int32)	Returns a DateTime that is set to the specified date and time in the current era.
	ToDateTime(Int32, Int32, Int32, Int32, Int32, Int32, Int32, Int32)	When overridden in a derived class, returns a DateTime that is set to the specified date and time in the specified era.
	ToFourDigitYear	Converts the specified year to a four-digit year by using the TwoDigitYearMax property to determine the appropriate century.
	ToString	Returns a string that represents the current object. (Inherited from Object.)

Top

Fields

	Name	Description
	CurrentEra	Represents the current era of the current calendar.

Top

Remarks

A calendar divides time into units, such as weeks, months, and years. The number, length, and start of the divisions vary in each calendar.

Any moment in time can be represented as a set of numeric values using a particular calendar. For example, a vernal equinox occurred at (1999, 3, 20, 8, 46, 0, 0.0) in the Gregorian calendar, that is, March 20, 1999 C.E. at 8:46:00:0.0. An implementation of Calendar can map any date in the range of a specific calendar to a similar set of numeric values, and DateTime can map such sets of numeric values to a textual representation using information from Calendar and DateTimeFormatInfo. The textual representation can be culture-sensitive, for example, "8:46 AM March 20th 1999 AD" for the en-US culture, or culture-insensitive, for example, "1999-03-20T08:46:00" in ISO 8601 format.

A Calendar implementation can define one or more eras. The Calendar class identifies the eras as enumerated integers, where the current era (CurrentEra) has the value 0.

To make up for the difference between the calendar year and the actual time that the earth rotates around the sun or the actual time that the moon rotates around the earth, a leap year has a different number of days from a standard calendar year. Each Calendar implementation defines leap years differently.

For consistency, the first unit in each interval (the first month, for example) is assigned the value 1.

The System.Globalization namespace includes the following Calendar implementations:

Examples

The following code example demonstrates the members of the Calendar class.

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())

      ' Uses the default calendar of the InvariantCulture.
      Dim myCal As Calendar = CultureInfo.InvariantCulture.Calendar

      ' Displays the values of the DateTime.
      outputBlock.Text += String.Format("April 3, 2002 of the Gregorian calendar:") & vbCrLf
      DisplayValues(outputBlock, 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.
      outputBlock.Text &= "After adding 5 to each component of the DateTime:" & 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 += String.Format("   Hour:         {0}", myCal.GetHour(myDT)) & vbCrLf
      outputBlock.Text += String.Format("   Minute:       {0}", myCal.GetMinute(myDT)) & vbCrLf
      outputBlock.Text += String.Format("   Second:       {0}", myCal.GetSecond(myDT)) & vbCrLf
      outputBlock.Text += String.Format("   Milliseconds: {0}", myCal.GetMilliseconds(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
'          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 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());

      // Uses the default calendar of the InvariantCulture.
      Calendar myCal = CultureInfo.InvariantCulture.Calendar;

      // Displays the values of the DateTime.
      outputBlock.Text += String.Format("April 3, 2002 of the Gregorian calendar:") + "\n";
      DisplayValues(outputBlock, 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.
      outputBlock.Text += "After adding 5 to each component of the DateTime:" + "\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 += String.Format("   Hour:         {0}", myCal.GetHour(myDT)) + "\n";
      outputBlock.Text += String.Format("   Minute:       {0}", myCal.GetMinute(myDT)) + "\n";
      outputBlock.Text += String.Format("   Second:       {0}", myCal.GetSecond(myDT)) + "\n";
      outputBlock.Text += String.Format("   Milliseconds: {0}", myCal.GetMilliseconds(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
   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

*/

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.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Condividi tramite