如何确定日期范围内是否有生日或周年纪念

鉴于我有生日/周年日期时间，我如何确定该日期是否在特定日期范围内发生？ 例如，

生日= 1/2/2000
日期范围= 12/25/2008 - 1/3/2009

我需要一种方法来确定此人的生日是否发生在该日期范围内 - 最好是用C＃。

我首先将生日DateTime的年份更改为与日期范围相匹配，然后检查“新”生日DateTime是否在日期范围的开始日期和结束日期之间......但是如果日期范围跨越不同年份，就像我上面的例子 - 我不得不添加一个讨厌的if语句。 有没有更好的办法？

---

好的，这是我的要求

public static bool IsBirthDayInRange(DateTime birthday, DateTime start, DateTime end)
{
    DateTime temp = birthday.AddYears(start.Year - birthday.Year);

    if (temp < start)
        temp = temp.AddYears(1);

    return birthday <= end && temp >= start && temp <= end;
}

---

我假设你的日期存储在DateTime变量中？ 如果是这样，比较非常简单：

if (Birthday > DateRangeLower && Birthday < DateRangeUpper) {
    // it's your birthday!
}

如果你喜欢，你可以用扩展方法封装它：

public static bool Between(this DateTime compareDate, DateTime startDate, DateTime endDate) {
    return compareDate > startDate && compareDate < endDate;
}

那么你可以这样称呼它：

if (Birthday.Between(DateRangeLower, DateRangeUpper) {
    // it's your birthday
}

更新 ：如果您要忽略生日的年份以确定日期周年是否在范围内，请应用以下内容：

if (DateRangeLower.DayOfYear <= DateRangeUpper.DayOfYear &&  
    Birthday.DayOfYear > DateRangeLower.DayOfYear && Birthday.DayOfYear < DateRangeUpper.DayOfYear) {
  // it's your birthday
  // the days are within the date range (and the range is in a single year)
}
else if (DateRangeLower.DayOfYear > DateRangeUpper.DayOfYear &&
    Birthday.DayOfYear < DateRangeLower.DayOfYear && Birthday.DayOfYear > DateRangeUpper.DayOfYear) {
  //  it's your birthday
  //  note, we're actually checking to see if the date is outside of the
  //  original date's days to handle the case where the dates span a year end boundary
  //  this only works if the dates are not more than 1 year apart
}

---

已更新答案以包含SLC提到的上限归一化。 这应该适用于那些人在29/02的情况下出生的情况。

DateTime birthday = new DateTime(2000, 2, 1);

DateTime min = new DateTime(2008, 12, 25);
DateTime max = new DateTime(2009, 3, 1);

DateTime nLower = new DateTime(min.Year, birthday.Month, birthday.Day);
DateTime nUpper = new DateTime(max.Year, birthday.Month, birthday.Day);

if (birthday.Year <= max.Year && 
    ((nLower >= min && nLower <= max) || (nUpper >= min && nUpper <= max)))
{
    // Happy birthday
    Console.WriteLine("Happy birthday");
}

现在一个处理当天出生的人的版本（29/02）：

public static bool IsBirthdayInRange(
    DateTime birthday, DateTime min, DateTime max)
{
    var dates = new  DateTime[] { birthday, min };
    for (int i = 0; i < dates.Length; i++)
    {
        if (dates[i].Month == 2 && dates[i].Day == 29)
        {
            dates[i] = dates[i].AddDays(-1);
        }
    }

    birthday = dates[0];
    min = dates[1];

    DateTime nLower = new DateTime(min.Year, birthday.Month, birthday.Day);
    DateTime nUpper = new DateTime(max.Year, birthday.Month, birthday.Day);

    if (birthday.Year <= max.Year &&
        ((nLower >= min && nLower <= max) || (nUpper >= min && nUpper <= max)))
    {
        return true;
    }

    return false;
}

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