TimeZoneInfo.AdjustmentRule Class

Definition

public: ref class TimeZoneInfo::AdjustmentRule sealed : IEquatable<TimeZoneInfo::AdjustmentRule ^>, System::Runtime::Serialization::IDeserializationCallback, System::Runtime::Serialization::ISerializable

public sealed class TimeZoneInfo.AdjustmentRule : IEquatable<TimeZoneInfo.AdjustmentRule>, System.Runtime.Serialization.IDeserializationCallback, System.Runtime.Serialization.ISerializable

[System.Serializable]
public sealed class TimeZoneInfo.AdjustmentRule : IEquatable<TimeZoneInfo.AdjustmentRule>, System.Runtime.Serialization.IDeserializationCallback, System.Runtime.Serialization.ISerializable

type TimeZoneInfo.AdjustmentRule = class
 interface IEquatable<TimeZoneInfo.AdjustmentRule>
 interface IDeserializationCallback
 interface ISerializable

type TimeZoneInfo.AdjustmentRule = class
 interface IDeserializationCallback
 interface ISerializable
 interface IEquatable<TimeZoneInfo.AdjustmentRule>

[<System.Serializable>]
type TimeZoneInfo.AdjustmentRule = class
 interface IEquatable<TimeZoneInfo.AdjustmentRule>
 interface ISerializable
 interface IDeserializationCallback

Public NotInheritable Class TimeZoneInfo.AdjustmentRule
Implements IDeserializationCallback, IEquatable(Of TimeZoneInfo.AdjustmentRule), ISerializable

Inheritance

Object

TimeZoneInfo.AdjustmentRule

Attributes

SerializableAttribute

Implements

IEquatable<TimeZoneInfo.AdjustmentRule> IDeserializationCallback ISerializable

Examples

The following example retrieves all time zones defined on the local system and displays complete information about their adjustment rules.

private enum WeekOfMonth 
{
 First = 1,
 Second = 2,
 Third = 3,
 Fourth = 4,
 Last = 5,
}

private static void ShowStartAndEndDates()
{
 // Get all time zones from system
 ReadOnlyCollection<TimeZoneInfo> timeZones = TimeZoneInfo.GetSystemTimeZones();
 string[] monthNames = CultureInfo.CurrentCulture.DateTimeFormat.MonthNames;
 // Get each time zone
 foreach (TimeZoneInfo timeZone in timeZones)
 {
 TimeZoneInfo.AdjustmentRule[] adjustments = timeZone.GetAdjustmentRules();
 // Display message for time zones with no adjustments
 if (adjustments.Length == 0)
 {
 Console.WriteLine("{0} has no adjustment rules", timeZone.StandardName);
 } 
 else
 {
 // Handle time zones with 1 or 2+ adjustments differently
 bool showCount = false;
 int ctr = 0;
 string spacer = "";
 
 Console.WriteLine("{0} Adjustment rules", timeZone.StandardName);
 if (adjustments.Length > 1)
 {
 showCount = true;
 spacer = " ";
 } 
 // Iterate adjustment rules
 foreach (TimeZoneInfo.AdjustmentRule adjustment in adjustments)
 {
 if (showCount)
 { 
 Console.WriteLine(" Adjustment rule #{0}", ctr+1);
 ctr++;
 }
 // Display general adjustment information
 Console.WriteLine("{0} Start Date: {1:D}", spacer, adjustment.DateStart);
 Console.WriteLine("{0} End Date: {1:D}", spacer, adjustment.DateEnd);
 Console.WriteLine("{0} Time Change: {1}:{2:00} hours", spacer, 
 adjustment.DaylightDelta.Hours, adjustment.DaylightDelta.Minutes);
 // Get transition start information
 TimeZoneInfo.TransitionTime transitionStart = adjustment.DaylightTransitionStart;
 Console.Write("{0} Annual Start: ", spacer);
 if (transitionStart.IsFixedDateRule)
 {
 Console.WriteLine("On {0} {1} at {2:t}", 
 monthNames[transitionStart.Month - 1], 
 transitionStart.Day, 
 transitionStart.TimeOfDay);
 }
 else
 {
 Console.WriteLine("The {0} {1} of {2} at {3:t}", 
 ((WeekOfMonth)transitionStart.Week).ToString(), 
 transitionStart.DayOfWeek.ToString(), 
 monthNames[transitionStart.Month - 1], 
 transitionStart.TimeOfDay);
 }
 // Get transition end information
 TimeZoneInfo.TransitionTime transitionEnd = adjustment.DaylightTransitionEnd;
 Console.Write("{0} Annual End: ", spacer);
 if (transitionEnd.IsFixedDateRule)
 {
 Console.WriteLine("On {0} {1} at {2:t}", 
 monthNames[transitionEnd.Month - 1], 
 transitionEnd.Day, 
 transitionEnd.TimeOfDay);
 }
 else
 {
 Console.WriteLine("The {0} {1} of {2} at {3:t}", 
 ((WeekOfMonth)transitionEnd.Week).ToString(), 
 transitionEnd.DayOfWeek.ToString(), 
 monthNames[transitionEnd.Month - 1], 
 transitionEnd.TimeOfDay);
 }
 }
 } 
 Console.WriteLine();
 } 
}

type WeekOfMonth = 
 | First = 1
 | Second = 2
 | Third = 3
 | Fourth = 4
 | Last = 5

let showStartAndEndDates () =
 // Get all time zones from system
 let timeZones = TimeZoneInfo.GetSystemTimeZones()
 let monthNames = CultureInfo.CurrentCulture.DateTimeFormat.MonthNames
 // Get each time zone
 for timeZone in timeZones do
 let adjustments = timeZone.GetAdjustmentRules()
 // Display message for time zones with no adjustments
 if adjustments.Length = 0 then
 printfn $"{timeZone.StandardName} has no adjustment rules"
 else
 // Handle time zones with 1 or 2+ adjustments differently
 let mutable ctr = 0
 let showCount, spacer = 
 if adjustments.Length > 1 then
 true, " "
 else 
 false, ""
 printfn $"{timeZone.StandardName} Adjustment rules"

 // Iterate adjustment rules
 for adjustment in adjustments do
 if showCount then
 printfn $" Adjustment rule #{ctr + 1}"
 ctr <- ctr + 1
 // Display general adjustment information
 printfn $"{spacer} Start Date: {adjustment.DateStart:D}"
 printfn $"{spacer} End Date: {adjustment.DateEnd:D}"
 printfn $"{spacer} Time Change: {adjustment.DaylightDelta.Hours}:{adjustment.DaylightDelta.Minutes:D2} hours"
 // Get transition start information
 let transitionStart = adjustment.DaylightTransitionStart
 printf $"{spacer} Annual Start: "
 if transitionStart.IsFixedDateRule then
 printfn $"On {monthNames[transitionStart.Month - 1]} {transitionStart.Day} at {transitionStart.TimeOfDay:t}"
 else
 printfn $"The {transitionStart.Week |> enum<WeekOfMonth>} {transitionStart.DayOfWeek} of {monthNames[transitionStart.Month - 1]} at {transitionStart.TimeOfDay:t}"
 // Get transition end information
 let transitionEnd = adjustment.DaylightTransitionEnd
 printf $"{spacer} Annual End: "
 if transitionEnd.IsFixedDateRule then
 printfn $"On {monthNames[transitionEnd.Month - 1]} {transitionEnd.Day} at {transitionEnd.TimeOfDay:t}"
 else
 printfn $"The {enum<WeekOfMonth> transitionEnd.Week} {transitionEnd.DayOfWeek} of {monthNames[transitionEnd.Month - 1]} at {transitionEnd.TimeOfDay:t}" 
 Console.WriteLine()

Private Enum WeekOfMonth As Integer
 First = 1
 Second = 2
 Third = 3
 Fourth = 4
 Last = 5
End Enum

Private Sub ShowStartAndEndDates()
 ' Get all time zones from system
 Dim timeZones As ReadOnlyCollection(Of TimeZoneInfo) = TimeZoneInfo.GetSystemTimeZones()
 ' Get each time zone
 For Each timeZone As TimeZoneInfo In timeZones
 Dim adjustments() As TimeZoneInfo.AdjustmentRule = timeZone.GetAdjustmentRules()
 ' Display message for time zones with no adjustments
 If adjustments.Length = 0 Then
 Console.WriteLine("{0} has no adjustment rules", timeZone.StandardName)
 Else
 ' Handle time zones with 1 or 2+ adjustments differently
 Dim showCount As Boolean = False
 Dim ctr As Integer = 0
 Dim spacer As String = ""
 
 Console.WriteLine("{0} Adjustment rules", timeZone.StandardName)
 If adjustments.Length > 1 Then showCount = True : spacer = " " 
 ' Iterate adjustment rules
 For Each adjustment As TimeZoneInfo.AdjustmentRule in adjustments
 If showCount Then 
 Console.WriteLine(" Adjustment rule #{0}", ctr+1)
 ctr += 1
 End If
 ' Display general adjustment information
 Console.WriteLine("{0} Start Date: {1:D}", spacer, adjustment.DateStart)
 Console.WriteLine("{0} End Date: {1:D}", spacer, adjustment.DateEnd)
 Console.WriteLine("{0} Time Change: {1}:{2:00} hours", spacer, _
 adjustment.DaylightDelta.Hours, adjustment.DaylightDelta.Minutes)
 ' Get transition start information
 Dim transitionStart As TimeZoneInfo.TransitionTime = adjustment.DaylightTransitionStart
 Console.Write("{0} Annual Start: ", spacer)
 If transitionStart.IsFixedDateRule Then
 Console.WriteLine("On {0} {1} at {2:t}", _
 MonthName(transitionStart.Month), _
 transitionStart.Day, _
 transitionStart.TimeOfDay)
 Else
 Console.WriteLine("The {0} {1} of {2} at {3:t}", _
 CType(transitionStart.Week, WeekOfMonth).ToString(), _
 transitionStart.DayOfWeek.ToString(), _
 MonthName(transitionStart.Month), _
 transitionStart.TimeOfDay)
 End If
 ' Get transition end information
 Dim transitionEnd As TimeZoneInfo.TransitionTime = adjustment.DaylightTransitionEnd
 
 Console.Write("{0} Annual End: ", spacer)
 If transitionEnd.IsFixedDateRule Then
 Console.WriteLine("On {0} {1} at {2:t}", _
 MonthName(transitionEnd.Month), _
 transitionEnd.Day, _
 transitionEnd.TimeOfDay)
 Else
 Console.WriteLine("The {0} {1} of {2} at {3:t}", _
 CType(transitionEnd.Week, WeekOfMonth).ToString(), _
 transitionEnd.DayOfWeek.ToString(), _
 MonthName(transitionEnd.Month), _
 transitionEnd.TimeOfDay)
 End If
 Next
 End If 
 Console.WriteLine()
 Next 
End Sub

The following is a small portion of the output that is generated by the example. The exact output will vary depending on the operating system and the date on which the example is run.

Morocco Standard Time Adjustment rules
 Adjustment rule #1
 Start Date: Tuesday, January 01, 2008
 End Date: Wednesday, December 31, 2008
 Time Change: 1:00 hours
 Annual Start: The Last Saturday of May at 11:59 PM
 Annual End: The Last Sunday of August at 11:59 PM
 Adjustment rule #2
 Start Date: Thursday, January 01, 2009
 End Date: Thursday, December 31, 2009
 Time Change: 1:00 hours
 Annual Start: The Last Sunday of May at 11:59 PM
 Annual End: The Third Thursday of August at 11:59 PM

Coordinated Universal Time has no adjustment rules

GMT Standard Time Adjustment rules
 Start Date: Monday, January 01, 0001
 End Date: Friday, December 31, 9999
 Time Change: 1:00 hours
 Annual Start: The Last Sunday of March at 1:00 AM
 Annual End: The Last Sunday of October at 2:00 AM

Greenwich Standard Time has no adjustment rules

W. Europe Standard Time Adjustment rules
 Start Date: Monday, January 01, 0001
 End Date: Friday, December 31, 9999
 Time Change: 1:00 hours
 Annual Start: The Last Sunday of March at 2:00 AM
 Annual End: The Last Sunday of October at 3:00 AM

Central Europe Standard Time Adjustment rules
 Start Date: Monday, January 01, 0001
 End Date: Friday, December 31, 9999
 Time Change: 1:00 hours
 Annual Start: The Last Sunday of March at 2:00 AM
 Annual End: The Last Sunday of October at 3:00 AM

Romance Standard Time Adjustment rules
 Start Date: Monday, January 01, 0001
 End Date: Friday, December 31, 9999
 Time Change: 1:00 hours
 Annual Start: The Last Sunday of March at 2:00 AM
 Annual End: The Last Sunday of October at 3:00 AM

Central European Standard Time Adjustment rules
 Start Date: Monday, January 01, 0001
 End Date: Friday, December 31, 9999
 Time Change: 1:00 hours
 Annual Start: The Last Sunday of March at 2:00 AM
 Annual End: The Last Sunday of October at 3:00 AM

W. Central Africa Standard Time has no adjustment rules

Remarks

The TimeZoneInfo.AdjustmentRule class defines the effective start and end dates of a particular time change to and from daylight saving time, respectively, as well as its delta (the exact amount by which the adjustment causes the time zone's standard time to change). In addition, two properties return TimeZoneInfo.TransitionTime objects that define when each transition to and from standard time occurs.

To create a TimeZoneInfo.AdjustmentRule object, call the static (Shared in Visual Basic) TimeZoneInfo.AdjustmentRule.CreateAdjustmentRule method. You can then supply an array of TimeZoneInfo.AdjustmentRule objects to two of the overloads of the TimeZoneInfo.CreateCustomTimeZone method. To retrieve the adjustment rules of a particular time zone, call its TimeZoneInfo.GetAdjustmentRules method, which returns an array of TimeZoneInfo.AdjustmentRule objects.

See also

• TimeZoneInfo