这是一个非常简单的方法：

int Age = DateTime.Today.Year - new DateTime(2000, 1, 1).Year;

我花了一些时间研究这个问题，并用这个来计算某人的年龄，以年、月和日为单位。我已经针对2月29日的问题和闰年进行了测试，它似乎奏效了，我希望得到任何反馈：

public void 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 +=
            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++;
    }

}

var birthDate = ... // DOB
var resultDate = DateTime.Now - birthDate;

使用resultDate，您可以应用TimeSpan财产来显示任何内容。

这里有一个解决方案。

DateTime dateOfBirth = new DateTime(2000, 4, 18);
DateTime currentDate = DateTime.Now;

int ageInYears = 0;
int ageInMonths = 0;
int ageInDays = 0;

ageInDays = currentDate.Day - dateOfBirth.Day;
ageInMonths = currentDate.Month - dateOfBirth.Month;
ageInYears = currentDate.Year - dateOfBirth.Year;

if (ageInDays < 0)
{
    ageInDays += DateTime.DaysInMonth(currentDate.Year, currentDate.Month);
    ageInMonths = ageInMonths--;

    if (ageInMonths < 0)
    {
        ageInMonths += 12;
        ageInYears--;
    }
}

if (ageInMonths < 0)
{
    ageInMonths += 12;
    ageInYears--;
}

Console.WriteLine("{0}, {1}, {2}", ageInYears, ageInMonths, ageInDays);

可以这么简单：

int age = DateTime.Now.AddTicks(0 - dob.Ticks).Year - 1;

TimeSpan diff = DateTime.Now - birthdayDateTime;
string age = String.Format("{0:%y} years, {0:%M} months, {0:%d}, days old", diff);

我不知道你到底希望它返回给你多少，所以我只是做了一个可读的字符串。