因为闰年和所有事情，我知道的最好的方法是：

DateTime birthDate = new DateTime(2000,3,1);
int age = (int)Math.Floor((DateTime.Now - birthDate).TotalDays / 365.25D);

这里有一个小的C#代码示例，我总结了一下，请注意边缘情况，特别是闰年，并不是所有上述解决方案都考虑到这些情况。将答案推出来作为DateTime可能会导致问题，因为你可能会在一个特定的月份中投入太多的时间，例如2月的30天。

public string LoopAge(DateTime myDOB, DateTime FutureDate)
{
    int years = 0;
    int months = 0;
    int days = 0;

    DateTime tmpMyDOB = new DateTime(myDOB.Year, myDOB.Month, 1);

    DateTime tmpFutureDate = new DateTime(FutureDate.Year, FutureDate.Month, 1);

    while (tmpMyDOB.AddYears(years).AddMonths(months) < tmpFutureDate)
    {
        months++;
        if (months > 12)
        {
            years++;
            months = months - 12;
        }
    }

    if (FutureDate.Day >= myDOB.Day)
    {
        days = days + FutureDate.Day - myDOB.Day;
    }
    else
    {
        months--;
        if (months < 0)
        {
            years--;
            months = months + 12;
        }
        days = days + (DateTime.DaysInMonth(FutureDate.AddMonths(-1).Year, FutureDate.AddMonths(-1).Month) + FutureDate.Day) - myDOB.Day;

    }

    //add an extra day if the dob is a leap day
    if (DateTime.IsLeapYear(myDOB.Year) && myDOB.Month == 2 && myDOB.Day == 29)
    {
        //but only if the future date is less than 1st March
        if(FutureDate >= new DateTime(FutureDate.Year, 3,1))
            days++;
    }

    return "Years: " + years + " Months: " + months + " Days: " + days;
}

这个经典问题值得野田时间来解决。

static int GetAge(LocalDate dateOfBirth)
{
    Instant now = SystemClock.Instance.Now;

    // The target time zone is important.
    // It should align with the *current physical location* of the person
    // you are talking about.  When the whereabouts of that person are unknown,
    // then you use the time zone of the person who is *asking* for the age.
    // The time zone of birth is irrelevant!

    DateTimeZone zone = DateTimeZoneProviders.Tzdb["America/New_York"];

    LocalDate today = now.InZone(zone).Date;

    Period period = Period.Between(dateOfBirth, today, PeriodUnits.Years);

    return (int) period.Years;
}

用法：

LocalDate dateOfBirth = new LocalDate(1976, 8, 27);
int age = GetAge(dateOfBirth);

您可能还对以下改进感兴趣：

将时钟作为IClock传递，而不是使用SystemClock.Instance，将提高可测试性。目标时区可能会更改，因此您也需要DateTimeZone参数。

另请参阅我关于这个主题的博客文章：处理生日和其他周年纪念日

我创建了一个Age结构，如下所示：

public struct Age : IEquatable<Age>, IComparable<Age>
{
    private readonly int _years;
    private readonly int _months;
    private readonly int _days;

    public int Years  { get { return _years; } }
    public int Months { get { return _months; } }
    public int Days { get { return _days; } }

    public Age( int years, int months, int days ) : this()
    {
        _years = years;
        _months = months;
        _days = days;
    }

    public static Age CalculateAge( DateTime dateOfBirth, DateTime date )
    {
        // Here is some logic that ressembles Mike's solution, although it
        // also takes into account months & days.
        // Ommitted for brevity.
        return new Age (years, months, days);
    }

    // Ommited Equality, Comparable, GetHashCode, functionality for brevity.
}

因为闰年和所有事情，我知道的最好的方法是：

DateTime birthDate = new DateTime(2000,3,1);
int age = (int)Math.Floor((DateTime.Now - birthDate).TotalDays / 365.25D);

我已经创建了一个SQL Server用户定义函数来计算某人的年龄，给定他们的出生日期。当您需要它作为查询的一部分时，这很有用：

using System;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;

public partial class UserDefinedFunctions
{
    [SqlFunction(DataAccess = DataAccessKind.Read)]
    public static SqlInt32 CalculateAge(string strBirthDate)
    {
        DateTime dtBirthDate = new DateTime();
        dtBirthDate = Convert.ToDateTime(strBirthDate);
        DateTime dtToday = DateTime.Now;

        // get the difference in years
        int years = dtToday.Year - dtBirthDate.Year;

        // subtract another year if we're before the
        // birth day in the current year
        if (dtToday.Month < dtBirthDate.Month || (dtToday.Month == dtBirthDate.Month && dtToday.Day < dtBirthDate.Day))
            years=years-1;

        int intCustomerAge = years;
        return intCustomerAge;
    }
};