DaylightTime Class
Assembly: mscorlib (in mscorlib.dll)
'Declaration <SerializableAttribute> _ <ComVisibleAttribute(True)> _ Public Class DaylightTime 'Usage Dim instance As 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( Integer ) method. Imports System Imports System.Globalization Imports Microsoft.VisualBasic Module DaylightChangesDemo ' Get the local time zone and a base local time. Dim localZone As TimeZone = TimeZone.CurrentTimeZone Sub CreateDaylightTime( year As Integer ) ' Create a DaylightTime object for the specified year. Dim daylight As DaylightTime = _ 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 ) End Sub Sub Main( ) Const headFmt As String = "{0,-7}{1,-20}{2,-20}{3}" Console.WriteLine( _ "This example of TimeZone.GetDaylightChanges( " & _ "Integer ) generates the " & vbCrLf & "following " & _ "output, which varies depending on the time zone " & _ "in which " & vbCrLf & "it is run. The example " & _ "creates DaylightTime objects for specified " & _ vbCrLf & "years and displays the start and end dates " & _ "and time change for " & vbCrLf & "daylight " & _ "saving time." & vbCrLf ) ' Write a message explaining that start dates prior to 1986 ' in the en-US culture may not be correct. If CultureInfo.CurrentCulture.Name = "en-US" Then Console.WriteLine( _ "Note: In the [en-US] culture, all start dates " & _ "are calculated from " & vbCrLf & "the first " & _ "Sunday in April, based on a standard set in " & _ "1986. For " & vbCrLf & "dates prior to 1986, " & _ "the calculated start date may not be accurate." ) End If Console.WriteLine( vbCrLf & "Local time: {0}" & vbCrLf, _ localZone.StandardName ) Console.WriteLine( headFmt, "Year", "Start", "End", "Change" ) Console.WriteLine( headFmt, "----", "-----", "---", "------" ) CreateDaylightTime( 1960 ) CreateDaylightTime( 1970 ) CreateDaylightTime( 1980 ) CreateDaylightTime( 1990 ) CreateDaylightTime( 2000 ) CreateDaylightTime( 2001 ) CreateDaylightTime( 2002 ) CreateDaylightTime( 2003 ) CreateDaylightTime( 2004 ) CreateDaylightTime( 2005 ) CreateDaylightTime( 2020 ) CreateDaylightTime( 2040 ) End Sub End Module ' This example of TimeZone.GetDaylightChanges( Integer ) 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
*/
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.