c# - 你如何使用出生日期计算 C# 中的年龄(考虑闰年)

Question

这里有个问题。我见过很多解决方案，但似乎没有一个能满足我想要的标准......

我想以这种格式显示年龄

20 y(s) 2 m(s) 20 d(s)
20 y(s) 2 m(s)
2 m(s) 20 d(s)
20 d(s)

等...

我尝试了几种解决方案，但闰年是我的问题所在。由于闰年，我的单元测试总是失败，无论中间有多少天，闰年都会计算额外的天数。

这是我的代码....

public static string AgeDiscription(DateTime dateOfBirth)
{
    var today = DateTime.Now;
    var days = GetNumberofDaysUptoNow(dateOfBirth);
    var months = 0;
    var years = 0;
    if (days > 365)
    {
        years = today.Year - dateOfBirth.Year;
        days = days % 365;
    }
    if (days > DateTime.DaysInMonth(today.Year, today.Month))
    {
        months = Math.Abs(today.Month - dateOfBirth.Month);
        for (int i = 0; i < months; i++)
        {
            days -= DateTime.DaysInMonth(today.Year, today.AddMonths(0 - i).Month);
        }
    }

    var ageDescription = new StringBuilder("");

    if (years != 0)
        ageDescription = ageDescription.Append(years + " y(s) ");
    if (months != 0)
        ageDescription = ageDescription.Append(months + " m(s) ");
    if (days != 0)
        ageDescription = ageDescription.Append(days + " d(s) ");

    return ageDescription.ToString();
}

public static int GetNumberofDaysUptoNow(DateTime dateOfBirth)
{
    var today = DateTime.Now;
    var timeSpan = today - dateOfBirth;
    var nDays = timeSpan.Days;
    return nDays;
}

有什么想法吗？？？

更新:

我希望两个日期之间的差异为:

var dateOfBirth = DateTime.Now.AddYears(-20);
string expected = "20 y(s) ";
string actual; // returns 20 y(s) 5 d(s)
actual = Globals.AgeDiscription(dateOfBirth);
Assert.AreEqual(expected, actual);

Answer 1

年龄是相当棘手的。这是我使用的结构的相关摘录。

public struct Age
{
    private readonly Int32 _years;
    private readonly Int32 _months;
    private readonly Int32 _days;
    private readonly Int32 _totalDays;

    /// <summary>
    /// Initializes a new instance of <see cref="Age"/>.
    /// </summary>
    /// <param name="start">The date and time when the age started.</param>
    /// <param name="end">The date and time when the age ended.</param>
    /// <remarks>This </remarks>
    public Age(DateTime start, DateTime end)
        : this(start, end, CultureInfo.CurrentCulture.Calendar)
    {
    }

    /// <summary>
    /// Initializes a new instance of <see cref="Age"/>.
    /// </summary>
    /// <param name="start">The date and time when the age started.</param>
    /// <param name="end">The date and time when the age ended.</param>
    /// <param name="calendar">Calendar used to calculate age.</param>
    public Age(DateTime start, DateTime end, Calendar calendar)
    {
        if (start > end) throw new ArgumentException("The starting date cannot be later than the end date.");

        var startDate = start.Date;
        var endDate = end.Date;

        _years = _months = _days = 0;
        _days += calendar.GetDayOfMonth(endDate) - calendar.GetDayOfMonth(startDate);
        if (_days < 0)
        {
            _days += calendar.GetDaysInMonth(calendar.GetYear(startDate), calendar.GetMonth(startDate));
            _months--;
        }
        _months += calendar.GetMonth(endDate) - calendar.GetMonth(startDate);
        if (_months < 0)
        {
            _months += calendar.GetMonthsInYear(calendar.GetYear(startDate));
            _years--;
        }
        _years += calendar.GetYear(endDate) - calendar.GetYear(startDate);

        var ts = endDate.Subtract(startDate);
        _totalDays = (Int32)ts.TotalDays;
    }

    /// <summary>
    /// Gets the number of whole years something has aged.
    /// </summary>
    public Int32 Years
    {
        get { return _years; }
    }

    /// <summary>
    /// Gets the number of whole months something has aged past the value of <see cref="Years"/>.
    /// </summary>
    public Int32 Months
    {
        get { return _months; }
    }

    /// <summary>
    /// Gets the age as an expression of whole months.
    /// </summary>
    public Int32 TotalMonths
    {
        get { return _years * 12 + _months; }
    }

    /// <summary>
    /// Gets the number of whole weeks something has aged past the value of <see cref="Years"/> and <see cref="Months"/>.
    /// </summary>
    public Int32 Days
    {
        get { return _days; }
    }

    /// <summary>
    /// Gets the total number of days that have elapsed since the start and end dates.
    /// </summary>
    public Int32 TotalDays
    {
        get { return _totalDays; }
    }

    /// <summary>
    /// Gets the number of whole weeks something has aged past the value of <see cref="Years"/> and <see cref="Months"/>.
    /// </summary>
    public Int32 Weeks
    {
        get { return (Int32) Math.Floor((Decimal) _days/7); }
    }

    /// <summary>
    /// Gets the age as an expression of whole weeks.
    /// </summary>
    public Int32 TotalWeeks
    {
        get { return (Int32) Math.Floor((Decimal) _totalDays/7); }
    }
}

这是一个通过的示例单元测试:

    [Test]
    public void Should_be_exactly_20_years_old()
    {
        var now = DateTime.Now;
        var age = new Age(now.AddYears(-20), now);

        Assert.That(age, Has.Property("Years").EqualTo(20)
            .And.Property("Months").EqualTo(0)
            .And.Property("Days").EqualTo(0));
    }