TimeZoneInfo.AdjustmentRule.DateEnd Property

 

Gets the date when the adjustment rule ceases to be in effect.

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

public DateTime DateEnd { get; }

Property Value

Type: System.DateTime

A DateTime value that indicates the end date of the adjustment rule.

The value of the DateEnd property is a date value without a time component.

Because the end date of the current adjustment rule is typically not known, you can assign DateTime.MaxValue.Date to the DateEnd property when you create a custom adjustment rule.

System_CAPS_importantImportant

   Unless there is a compelling reason to do otherwise, you should define the adjustment rule's end date to occur within the time interval during which the time zone observes standard time. Unless there is a compelling reason to do so, you should not define the adjustment rule's end date to occur within the time interval during which the time zone observes daylight saving time. For example, if a time zone's transition from daylight saving time occurs on the third Sunday of March and its transition to daylight saving time occurs on the first Sunday of October, the effective end date of the adjustment rule should not be December 31 of a particular year, since that date occurs within the period of daylight saving time.

By default, the registry in Windows XP defines a single adjustment rule whose end date is Friday, December 31, 9999 (the value of DateTime.MaxValue.Date), for each time zone. For time zones in the United States, the registry in Windows Vista defines two adjustment rules:

  • Monday, January 01, 0001, to Sunday, December 31, 2006.

  • Monday, January 01, 2007, to Friday, December 31, 9999.

This means that, although time zone adjustment rules stored in the registry are useful for performing current time zone-related operations, they cannot be reliably used for retrieving historical time zone information. For information about defining a custom time zone with multiple adjustment rules that can be used in a historical time zone-aware application, see How to: Create Time Zones with Adjustment Rules.

The following example displays information about all of the time zones defined in the local computer's system registry, including the starting and ending dates of their adjustment rules.

using System;
using System.Collections.ObjectModel;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      ReadOnlyCollection<TimeZoneInfo> timeZones = TimeZoneInfo.GetSystemTimeZones();
      DateTimeFormatInfo dateInfo = CultureInfo.CurrentCulture.DateTimeFormat;

      foreach (var zone in timeZones)
      {
         Console.WriteLine("{0} transition time information:", zone.StandardName);
         Console.WriteLine("   Time zone information: ");
         Console.WriteLine("      Base UTC Offset: {0}", zone.BaseUtcOffset);
         Console.WriteLine("      Supports DST: {0}", zone.SupportsDaylightSavingTime);

         TimeZoneInfo.AdjustmentRule[] adjustmentRules= zone.GetAdjustmentRules();

         // Indicate that time zone has no adjustment rules
         if (adjustmentRules.Length == 0) {
            Console.WriteLine("      No adjustment rules defined.");
         }   
         else {
            Console.WriteLine("      Adjustment Rules: {0}", adjustmentRules.Length);
            // Iterate adjustment rules       
            foreach (var adjustmentRule in adjustmentRules) {
               Console.WriteLine("   Adjustment rule from {0:d} to {1:d}:", 
                                 adjustmentRule.DateStart, 
                                 adjustmentRule.DateEnd);                                 
               Console.WriteLine("      Delta: {0}", adjustmentRule.DaylightDelta);
               // Get start of transition
               TimeZoneInfo.TransitionTime daylightStart = adjustmentRule.DaylightTransitionStart;
               // Display information on floating date rule
               if (! daylightStart.IsFixedDateRule)
                  Console.WriteLine("      Begins at {0:t} on the {1} {2} of {3}", 
                                 daylightStart.TimeOfDay, 
                                 (WeekOfMonth) daylightStart.Week,  
                                 daylightStart.DayOfWeek, 
                                 dateInfo.GetMonthName(daylightStart.Month));
               // Display information on fixed date rule 
               else
                  Console.WriteLine("      Begins at {0:t} on {1} {2}", 
                                    daylightStart.TimeOfDay, 
                                    dateInfo.GetMonthName(daylightStart.Month), 
                                    daylightStart.Day);

               // Get end of transition.
              TimeZoneInfo.TransitionTime daylightEnd = adjustmentRule.DaylightTransitionEnd;
               // Display information on floating date rule.
               if (!daylightEnd.IsFixedDateRule) 
                  Console.WriteLine("      Ends at {0:t} on the {1} {2} of {3}", 
                                 daylightEnd.TimeOfDay, 
                                 (WeekOfMonth) daylightEnd.Week,  
                                 daylightEnd.DayOfWeek, 
                                 dateInfo.GetMonthName(daylightEnd.Month));
               // Display information on fixed date rule.
               else
                  Console.WriteLine("      Ends at {0:t} on {1} {2}", 
                                    daylightEnd.TimeOfDay, 
                                    dateInfo.GetMonthName(daylightEnd.Month), 
                                    daylightEnd.Day);
            }
         }   
      }   
   }

   private enum WeekOfMonth 
   {
      First = 1,
      Second = 2,
      Third = 3,
      Fourth = 4,
      Last = 5,
   }
}
// A portion of the output from the example might appear as follows:
//       Tonga Standard Time transition time information:
//          Time zone information:
//             Base UTC Offset: 13:00:00
//             Supports DST: False
//             No adjustment rules defined.
//       Samoa Standard Time transition time information:
//          Time zone information:
//             Base UTC Offset: 13:00:00
//             Supports DST: True
//             Adjustment Rules: 4
//          Adjustment rule from 1/1/0001 to 12/31/2009:
//             Delta: 00:00:00
//             Begins at 12:00 AM on January 1
//             Ends at 12:00 AM on January 1
//          Adjustment rule from 1/1/2010 to 12/31/2010:
//             Delta: 01:00:00
//             Begins at 11:59 PM on the Last Saturday of September
//             Ends at 12:00 AM on the First Friday of January
//          Adjustment rule from 1/1/2011 to 12/31/2011:
//             Delta: 01:00:00
//             Begins at 3:00 AM on the Fourth Saturday of September
//             Ends at 4:00 AM on the First Saturday of April
//          Adjustment rule from 1/1/2012 to 12/31/9999:
//             Delta: 01:00:00
//             Begins at 12:00 AM on the Last Sunday of September
//             Ends at 1:00 AM on the First Sunday of April
//       Line Islands Standard Time transition time information:
//          Time zone information:
//             Base UTC Offset: 14:00:00
//             Supports DST: False
//             No adjustment rules defined.

.NET Framework
Available since 3.5
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