Question

我正在尝试使用DaylightSavingTime查找时区和返回时间？

我可以：

找到时区
获取utc offset
根据
确定时区是否使用DaylightSavingTime
获取DaylightSavingTime的规则
确定当前时间是否使用DaylightSavingTime

但是我在应用规则时遇到问题，这里是代码：

FYI

System.DateTime.Now.ToUniversalTime().Add(timeDiffUtcClient) return = 2010/07/10 09:25:45 AM

 DateTime localDate = System.DateTime.Now.ToUniversalTime();
// Get the venue time zone info
TimeZoneInfo tz = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
TimeSpan timeDiffUtcClient = tz.BaseUtcOffset;
localDate = System.DateTime.Now.ToUniversalTime().Add(timeDiffUtcClient);


if (tz.SupportsDaylightSavingTime && tz.IsDaylightSavingTime(localDate))
{
    localDate = localDate.Subtract(tz.GetAdjustmentRules().Single(r => localDate >= r.DateStart && localDate <= r.DateEnd).DaylightDelta);
}
DateTimeOffset utcDate = localDate.ToUniversalTime();


return localDate;

最终值 localDate 是{2010/07/10 08:20:40 AM}

应该是{2010/07/10 09:20:40 AM}

由于某种原因，这是1小时。

Answer 1

好吧，我修好了：

 public static DateTime GetLocalTime(string TimeZoneName)
    {
        DateTime localDate = System.DateTime.Now.ToUniversalTime();

        // Get the venue time zone info
        TimeZoneInfo tz = TimeZoneInfo.FindSystemTimeZoneById(TimeZoneName);
        TimeSpan timeDiffUtcClient = tz.BaseUtcOffset;
        localDate = System.DateTime.Now.ToUniversalTime().Add(timeDiffUtcClient);
        //DateTimeOffset localDate = new DateTimeOffset(venueTime, tz.BaseUtcOffset);

        if (tz.SupportsDaylightSavingTime && tz.IsDaylightSavingTime(localDate))
        {
            TimeZoneInfo.AdjustmentRule[] rules = tz.GetAdjustmentRules();
            foreach (var adjustmentRule in rules)
            {
                if (adjustmentRule.DateStart <= localDate && adjustmentRule.DateEnd >= localDate)
                {
                    localDate = localDate.Add(adjustmentRule.DaylightDelta);
                }
            }
            //localDate = localDate.Subtract(tz.GetAdjustmentRules().Single(r => localDate >= r.DateStart && localDate <= r.DateEnd).DaylightDelta);
        }
        DateTimeOffset utcDate = localDate.ToUniversalTime();


        return localDate;
    }

要测试它，你可以这样做：

Hashtable list = new Hashtable();
        foreach (TimeZoneInfo tzi in TimeZoneInfo.GetSystemTimeZones())
        {
            string name = tzi.DisplayName;
            DateTime localtime = TimeZoneHelper.GetLocalTime(tzi.Id);
            list.Add(name, localtime);
        }

然后在最后的“列表”上做一个快速观察并转到worldtimeserver.com并确认几个城市。

Answer 2

我在这里跳了一下，但我不确定你为什么要手动完成这一切。您的整个功能无法替换为：

public static DateTime GetLocalTime(string TimeZoneName)
{
  return TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, TimeZoneInfo.FindSystemTimeZoneById(TimeZoneName));
}

如何应用DaylightSavingTime查找时区和返回时间？

2 个答案: