将 DateTimeOffset 与夏令时进行比较

Question

这里的 DateTimeOffset 实例代表相同的时间，但一个实例有 DST 而另一个没有。 我想比较没有 DST 的实例，所以结果是 True。

using System;

var today = DateTime.Today;

// Today YYYY-MM-01
var firstDayMonth = new DateTimeOffset(
    new DateTime(today.Year, today.Month, 1, 0, 0, 0, today.Kind).AddHours(12));

// Add year offset from 2000
DateTimeOffset withYearOffset = firstDayMonth.AddYears(2000 - firstDayMonth.Year);

// Add month offset from 1
var withMonthOffset = withYearOffset.AddMonths(1 - withYearOffset.Month);

// Add day offset from 1
var calculated_dt_2000_1_1_12_0_0 = withMonthOffset.AddDays(1 - withMonthOffset.Day);

// 01.01.2000 12:00:00 +03:00
Console.WriteLine(calculated_dt_2000_1_1_12_0_0);

var dt_2000_1_1_12_0_0 = new DateTimeOffset(new DateTime(2000, 1, 1).AddHours(12));

// 01.01.2000 12:00:00 + 02:00
Console.WriteLine(dt_2000_1_1_12_0_0);

// False
Console.WriteLine(calculated_dt_2000_1_1_12_0_0.Equals(dt_2000_1_1_12_0_0));

Answer 1

转换为 UTC 可以解决问题。

var calculated_dt_2000_1_1_12_0_0 = withMonthOffset.ToUniversalTime().AddHours(firstDayMonth.Offset.Hours);


var dt_2000_1_1_12_0_0_withOffset = new DateTimeOffset(new DateTime(2000, 1, 1).AddHours(12));
var dt_2000_1_1_12_0_0 = dt_2000_1_1_12_0_0_withOffset.ToUniversalTime().AddHours(dt_2000_1_1_12_0_0_withOffset.Offset.Hours);