C# .NET TimeZone.CurrentTimeZone.GetDaylightChanges返回错误的2005年DST

我使用下面的代码来显示2005年到2035年间的夏令时

对于2005年，这表明DST在4月3日至10月30日之间。但是GetDaylightChanges会在3月13日和11月6日返回

.NET GetDaylightChanges是可靠的函数吗

    public static void GetCurrentTimeZone()
    {
        for (int i = 0; i < 30; i++)
        {
            var dlt = TimeZone.CurrentTimeZone.GetDaylightChanges(2005 + i);

            Console.WriteLine(2005 + i);
            Console.WriteLine(dlt.Start.ToLongDateString());
            Console.WriteLine(dlt.End.ToLongDateString());

            Console.WriteLine(" ");
        }
    }

公共静态无效GetCurrentTimeZone（）
{
对于（int i=0；i<30；i++）
{
var dlt=TimeZone.CurrentTimeZone.GetDaylightChanges（2005+i）；
控制台写入线（2005+i）；
Console.WriteLine（dlt.Start.ToLongDateString（））；
Console.WriteLine（dlt.End.ToLongDateString（））；
控制台。写线（“”）；
}
}

从1987年到2006年，规定是：DST从4月的第一个星期日到10月的最后一个星期日有效

从2007年至今，规定是：DST从3月的第二个星期日到11月的第一个星期日有效

然而，@MaheshKava指出，GetDaylightChangesAPI的备注部分指出：

因为TimeZone类只支持一个夏令时 调整规则，GetDaylightChanges方法应用当前 调整规则适用于任何年份，无论调整规则 实际上适用于那一年

这意味着当前规则（3月的第2个星期日至11月的第1个星期日）适用于所有年份，无论该规则是否在该年内有效。因此，总而言之，GetDaylightChanges将为您提供2007年之前任何一年的不准确结果，显然这是故意的

API文档进一步说明，您可以使用TimeZoneInfo.GetAdjustmentRules获得更准确的信息。我对此很好奇，所以我写了以下代码：

    static void Main(string[] args)
    {
        PrintAllDaylightSavingsAdjustmentDates();
        Console.ReadLine();
    }

    public static void PrintAllDaylightSavingsAdjustmentDates()
    {
        TimeZoneInfo timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
        TimeZoneInfo.AdjustmentRule[] adjustmentRules = timeZoneInfo.GetAdjustmentRules();

        for (int year = 2000; year < 2030; year++)
        {
            PrintDaylightSavingsAdjustmentDatesForYear(adjustmentRules, year);
        }
    }

    public static void PrintDaylightSavingsAdjustmentDatesForYear
        (
        TimeZoneInfo.AdjustmentRule[] adjustmentRules, 
        int year
        )
    {
        DateTime firstOfYear = new DateTime(year, 1, 1);

        foreach (TimeZoneInfo.AdjustmentRule adjustmentRule in adjustmentRules)
        {
            if ((adjustmentRule.DateStart <= firstOfYear) && (firstOfYear <= adjustmentRule.DateEnd))
            {
                Console.WriteLine("In {0}, DST started on {1} and ended on {2}.",
                    year,
                    GetTransitionDate(adjustmentRule.DaylightTransitionStart, year).ToString("MMMM dd"),
                    GetTransitionDate(adjustmentRule.DaylightTransitionEnd, year).ToString("MMMM dd"));
            }
        }
    }

    public static DateTime GetTransitionDate
        (
        TimeZoneInfo.TransitionTime transitionTime,
        int year
        )
    {
        if (transitionTime.IsFixedDateRule)
        {
            return new DateTime(year, transitionTime.Month, transitionTime.Day);
        }
        else
        {
            if (transitionTime.Week == 5)
            {
                // Special value meaning the last DayOfWeek (e.g., Sunday) in the month.
                DateTime transitionDate = new DateTime(year, transitionTime.Month, 1);
                transitionDate = transitionDate.AddMonths(1);

                transitionDate = transitionDate.AddDays(-1);
                while (transitionDate.DayOfWeek != transitionTime.DayOfWeek)
                {
                    transitionDate = transitionDate.AddDays(-1);
                }

                return transitionDate;
            }
            else
            {
                DateTime transitionDate = new DateTime(year, transitionTime.Month, 1);
                transitionDate = transitionDate.AddDays(-1);

                for (int howManyWeeks = 0; howManyWeeks < transitionTime.Week; howManyWeeks++)
                {
                    transitionDate = transitionDate.AddDays(1);
                    while (transitionDate.DayOfWeek != transitionTime.DayOfWeek)
                    {
                        transitionDate = transitionDate.AddDays(1);
                    }
                }

                return transitionDate;
            }
        }
    }

---

哪个国家的DST？那个国家的哪个时区？具体来说，什么是CurrentTimeZone？请阅读备注部分。NET的哪个版本？对我来说至少是4.5。@Eric：我在问OPA，这是一个相当糟糕的API设计，即使有文档记录。我同意@EricJ。我不清楚为什么他们不能使GetDaylightChanges API正确运行。@RajeevGoel-时区

API在所有实际用途中都不推荐使用。“尽可能使用
TimeZoneInfo
类而不是
TimeZone
类。”该类仅用于旧版支持，并且已从即将到来的CORECRL项目中删除。（如果由我决定，它早就被删除了。）我如何从你的例子中得到准确的时间部分，而不是12点
In 2000, DST started on April 02 and ended on October 29.
In 2001, DST started on April 01 and ended on October 28.
In 2002, DST started on April 07 and ended on October 27.
In 2003, DST started on April 06 and ended on October 26.
In 2004, DST started on April 04 and ended on October 31.
In 2005, DST started on April 03 and ended on October 30.
In 2006, DST started on April 02 and ended on October 29.
In 2007, DST started on March 11 and ended on November 04.
In 2008, DST started on March 09 and ended on November 02.
In 2009, DST started on March 08 and ended on November 01.
In 2010, DST started on March 14 and ended on November 07.
In 2011, DST started on March 13 and ended on November 06.
In 2012, DST started on March 11 and ended on November 04.
In 2013, DST started on March 10 and ended on November 03.
In 2014, DST started on March 09 and ended on November 02.
In 2015, DST started on March 08 and ended on November 01.
In 2016, DST started on March 13 and ended on November 06.
In 2017, DST started on March 12 and ended on November 05.
In 2018, DST started on March 11 and ended on November 04.
In 2019, DST started on March 10 and ended on November 03.
In 2020, DST started on March 08 and ended on November 01.
In 2021, DST started on March 14 and ended on November 07.
In 2022, DST started on March 13 and ended on November 06.
In 2023, DST started on March 12 and ended on November 05.
In 2024, DST started on March 10 and ended on November 03.
In 2025, DST started on March 09 and ended on November 02.
In 2026, DST started on March 08 and ended on November 01.
In 2027, DST started on March 14 and ended on November 07.
In 2028, DST started on March 12 and ended on November 05.
In 2029, DST started on March 11 and ended on November 04.