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DaylightTime Class

Defines the period of daylight-saving time.

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

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public ref class DaylightTime
/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
public class DaylightTime
SerializableAttribute 
ComVisibleAttribute(true) 
public class DaylightTime

Daylight-saving time is a period during the year when the time is advanced, usually by an hour, to take advantage of the extended daylight hours. At the end of the period, the time is set back to the standard time.

The DaylightTime class is used extensively by members of the System.TimeZone class.

The following code example uses the TimeZone.GetDaylightChanges method to return the daylight saving time period and offset for selected years.

// Example of the TimeZone::GetDaylightChanges( int ) method.
using namespace System;
using namespace System::Globalization;
void CreateDaylightTime( int year, TimeZone^ localZone )
{
   
   // Create a DaylightTime object for the specified year.
   DaylightTime^ daylight = localZone->GetDaylightChanges( year );
   
   // Display the start and end dates and the time change.
   Console::WriteLine( "{0,-7}{1,-20:yyyy-MM-dd HH:mm}"
   "{2,-20:yyyy-MM-dd HH:mm}{3}", year, daylight->Start, daylight->End, daylight->Delta );
}

int main()
{
   String^ headFmt = "{0,-7}{1,-20}{2,-20}{3}";
   
   // Get the local time zone.
   TimeZone^ localZone = TimeZone::CurrentTimeZone;
   Console::WriteLine( "This example of TimeZone::GetDaylightChanges( int ) "
   "generates the \nfollowing output, which varies "
   "depending on the time zone in which \nit is run. The "
   "example creates DaylightTime objects for specified \n"
   "years and displays the start and end dates and time "
   "change for \ndaylight saving time.\n" );
   
   // Write a message explaining that start dates prior to 1986 
   // in the en-US culture may not be correct.
   // ( CultureInfo::CurrentCulture->Name == S"en-US" ) returns False.
   if ( CultureInfo::CurrentCulture->Name->CompareTo( "en-US" ) == 0 )
   {
      Console::WriteLine( "Note: In the [en-US] culture, all start dates are "
      "calculated from \nthe first Sunday in April, based on "
      "a standard set in 1986. For \ndates prior to 1986, "
      "the calculated start date may not be accurate." );
   }

   Console::WriteLine( "\nLocal time: {0}\n", localZone->StandardName );
   Console::WriteLine( headFmt, "Year", "Start", "End", "Change" );
   Console::WriteLine( headFmt, "----", "-----", "---", "------" );
   CreateDaylightTime( 1960, localZone );
   CreateDaylightTime( 1970, localZone );
   CreateDaylightTime( 1980, localZone );
   CreateDaylightTime( 1990, localZone );
   CreateDaylightTime( 2000, localZone );
   CreateDaylightTime( 2001, localZone );
   CreateDaylightTime( 2002, localZone );
   CreateDaylightTime( 2003, localZone );
   CreateDaylightTime( 2004, localZone );
   CreateDaylightTime( 2005, localZone );
   CreateDaylightTime( 2020, localZone );
   CreateDaylightTime( 2040, localZone );
}

/*
This example of TimeZone::GetDaylightChanges( int ) generates the
following output, which varies depending on the time zone in which
it is run. The example creates DaylightTime objects for specified
years and displays the start and end dates and time change for
daylight saving time.

Note: In the [en-US] culture, all start dates are calculated from
the first Sunday in April, based on a standard set in 1986. For
dates prior to 1986, the calculated start date may not be accurate.

Local time: Pacific Standard Time

Year   Start               End                 Change
----   -----               ---                 ------
1960   1960-04-03 02:00    1960-10-30 02:00    01:00:00
1970   1970-04-05 02:00    1970-10-25 02:00    01:00:00
1980   1980-04-06 02:00    1980-10-26 02:00    01:00:00
1990   1990-04-01 02:00    1990-10-28 02:00    01:00:00
2000   2000-04-02 02:00    2000-10-29 02:00    01:00:00
2001   2001-04-01 02:00    2001-10-28 02:00    01:00:00
2002   2002-04-07 02:00    2002-10-27 02:00    01:00:00
2003   2003-04-06 02:00    2003-10-26 02:00    01:00:00
2004   2004-04-04 02:00    2004-10-31 02:00    01:00:00
2005   2005-04-03 02:00    2005-10-30 02:00    01:00:00
2020   2020-04-05 02:00    2020-10-25 02:00    01:00:00
2040   2040-04-01 02:00    2040-10-28 02:00    01:00:00
*/

// Example of the TimeZone.GetDaylightChanges( int ) method.
import System.*;
import System.Globalization.*;

class DaylightChangesDemo
{
    // Get the local time zone and a base local time.
    private static TimeZone localZone = TimeZone.get_CurrentTimeZone();
   
    static void CreateDaylightTime(int year) 
    {
        // Create a DaylightTime object for the specified year.
        DaylightTime daylight = localZone.GetDaylightChanges(year);
      
         // Display the start and end dates and the time change.
        Console.WriteLine("{0,-7}{1,-20:yyyy-MM-dd HH:mm}"
            + "{2,-20:yyyy-MM-dd HH:mm}{3}", new Object[] {
            (System.Int32)year, daylight.get_Start(), daylight.get_End(),
            daylight.get_Delta() } );
    } //CreateDaylightTime
      
    public static void main(String[] args)
    {
        final String headFmt = "{0,-7}{1,-20}{2,-20}{3}";
      
        Console.WriteLine(("This example of TimeZone.GetDaylightChanges( int )"
            + " generates the \nfollowing output, which varies "
            + "depending on the time zone in which \nit is run. The " 
            + "example creates DaylightTime objects for specified \n" 
            + "years and displays the start and end dates and time " 
            + "change for \ndaylight saving time.\n"));
      
        // Write a message explaining that start dates prior to 1986 
        // in the en-US culture may not be correct.
        if(CultureInfo.get_CurrentCulture().get_Name()
            .equalsIgnoreCase("en-US")) {
                Console.WriteLine(("Note: In the [en-US] culture, all"
                    + " start dates are calculated from \nthe first Sunday in April, "
                    + "based on a standard set in 1986. For \ndates " 
                    + "prior to 1986, the calculated start date may not " 
                    + "be accurate."));
        }
      
        Console.WriteLine("\nLocal time: {0}\n", localZone.get_StandardName());
        Console.WriteLine(headFmt, new Object[] { "Year", "Start", "End",
            "Change" });
        Console.WriteLine(headFmt, new Object[] { "----", "-----", "---",
            "------" });
      
        CreateDaylightTime(1960);
        CreateDaylightTime(1970);
        CreateDaylightTime(1980);
        CreateDaylightTime(1990);
        CreateDaylightTime(2000);
        CreateDaylightTime(2001);
        CreateDaylightTime(2002);
        CreateDaylightTime(2003);
        CreateDaylightTime(2004);
        CreateDaylightTime(2005);
        CreateDaylightTime(2020);
        CreateDaylightTime(2040);
    } //main
} //DaylightChangesDemo

/*
This example of TimeZone.GetDaylightChanges( int ) generates the
following output, which varies depending on the time zone in which
it is run. The example creates DaylightTime objects for specified
years and displays the start and end dates and time change for
daylight saving time.

Note: In the [en-US] culture, all start dates are calculated from
the first Sunday in April, based on a standard set in 1986. For
dates prior to 1986, the calculated start date may not be accurate.

Local time: Pacific Standard Time

Year   Start               End                 Change
----   -----               ---                 ------
1960   1960-04-03 02:00    1960-10-30 02:00    01:00:00
1970   1970-04-05 02:00    1970-10-25 02:00    01:00:00
1980   1980-04-06 02:00    1980-10-26 02:00    01:00:00
1990   1990-04-01 02:00    1990-10-28 02:00    01:00:00
2000   2000-04-02 02:00    2000-10-29 02:00    01:00:00
2001   2001-04-01 02:00    2001-10-28 02:00    01:00:00
2002   2002-04-07 02:00    2002-10-27 02:00    01:00:00
2003   2003-04-06 02:00    2003-10-26 02:00    01:00:00
2004   2004-04-04 02:00    2004-10-31 02:00    01:00:00
2005   2005-04-03 02:00    2005-10-30 02:00    01:00:00
2020   2020-04-05 02:00    2020-10-25 02:00    01:00:00
2040   2040-04-01 02:00    2040-10-28 02:00    01:00:00
*/

System.Object
  System.Globalization.DaylightTime

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

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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