在C#中计算重复日期的正确方法

Every Day
Every Week
Every 2 Weeks
Every 3 Weeks
Every Month
Every 2 Months
...

这样做的正确方法是什么？它应该可以正常使用不同的时区和日节省时间设置.我想我应该在本地DateTime中添加几天/几周/月,然后将其转换为UTC.但我不确定这一点.如果我添加几天会发生什么,这将是我们需要向前调整我们的时钟一小时的时间.在这种情况下,此时间不存在.

下面是我写的代码,但我不确定它在每种情况下都能正常工作：

private static List<DateTime> FindOccurrences(DateTime localStart,Repeat repeat,int occurrences)
{
    var result = new List<DateTime> { localStart };
    switch (repeat)
    {
        case Repeat.Daily:
            for (int i = 1; i <= occurrences; i++)
                result.Add(localStart.AddDays(i));
            break;
        case Repeat.Every2Weeks:
            for (int i = 1; i <= occurrences; i++)
                result.Add(localStart.AddDays((7 * 2) * i));
            break;
        ...
    }
    return result;
}

public List<Event> CreateRepeating(string timeZone,int repeatEnds,DateTime localStart,int eventDuration)
{
    var events = new List<Event>();
    var occurrences = FindOccurrences(localStart,repeat,repeatEnds);
    foreach (var occurrence in occurrences)
    {
        var item = new Event();
        item.Start = occurrence.ToUtcTime(timeZone);
        item.End = occurrence.ToUtcTime(timeZone).AddMinutes(eventDuration);
        events.Add(item);
    }
    return events;
}

PS：
所有日期都以UTC格式存储在数据库中.