TimeZoneInfo.AdjustmentRule Class

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Source:

TimeZoneInfo.AdjustmentRule.cs

Provides information about a time zone adjustment, such as the transition to and from daylight saving time.

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

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

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

Inheritance

Object

TimeZoneInfo.AdjustmentRule

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.

Note

An instance of the TimeZoneInfo.AdjustmentRule class is immutable. Once an object has been created, its values cannot be modified.

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.

Properties

BaseUtcOffsetDelta	Gets the time difference with the base UTC offset for the time zone during the adjustment-rule period.
DateEnd	Gets the date when the adjustment rule ceases to be in effect.
DateStart	Gets the date when the adjustment rule takes effect.
DaylightDelta	Gets the amount of time that is required to form the time zone's daylight saving time. This amount of time is added to the time zone's offset from Coordinated Universal Time (UTC).
DaylightTransitionEnd	Gets information about the annual transition from daylight saving time back to standard time.
DaylightTransitionStart	Gets information about the annual transition from standard time to daylight saving time.

Methods

CreateAdjustmentRule(DateTime, DateTime, TimeSpan, TimeZoneInfo+TransitionTime, TimeZoneInfo+TransitionTime)	Creates a new adjustment rule for a particular time zone.
CreateAdjustmentRule(DateTime, DateTime, TimeSpan, TimeZoneInfo+TransitionTime, TimeZoneInfo+TransitionTime, TimeSpan)	Creates a new adjustment rule for a particular time zone.
Equals(Object)	Indicates whether the current instance is equal to another instance.
Equals(TimeZoneInfo+AdjustmentRule)	Determines whether the current TimeZoneInfo.AdjustmentRule object is equal to a second TimeZoneInfo.AdjustmentRule object.
GetHashCode()	Serves as a hash function for hashing algorithms and data structures such as hash tables.
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

Explicit Interface Implementations

IDeserializationCallback.OnDeserialization(Object)	Runs when the deserialization of a TimeZoneInfo.AdjustmentRule object is completed.
ISerializable.GetObjectData(SerializationInfo, StreamingContext)	Populates a SerializationInfo object with the data that is required to serialize this object.

See also

• TimeZoneInfo