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DaylightTime Class

Defines the period of daylight saving time.

System.Object
  System.Globalization.DaylightTime

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

'Declaration
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Class DaylightTime

The DaylightTime type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkDaylightTimeInitializes a new instance of the DaylightTime class.
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  NameDescription
Public propertySupported by the XNA FrameworkDeltaGets the TimeSpan that represents the difference between the standard time and the daylight saving time.
Public propertySupported by the XNA FrameworkEndGets the DateTime that represents the date and time when the daylight saving period ends.
Public propertySupported by the XNA FrameworkStartGets the DateTime that represents the date and time when the daylight saving period begins.
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  NameDescription
Public methodSupported by the XNA FrameworkEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodSupported by the XNA FrameworkFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by the XNA FrameworkGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodSupported by the XNA FrameworkGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by the XNA FrameworkMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by the XNA FrameworkToStringReturns a string that represents the current object. (Inherited from Object.)
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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(Int32) 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


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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