我使用这个：

public static class DateTimeExtensions
{
    public static int Age(this DateTime birthDate)
    {
        return Age(birthDate, DateTime.Now);
    }

    public static int Age(this DateTime birthDate, DateTime offsetDate)
    {
        int result=0;
        result = offsetDate.Year - birthDate.Year;

        if (offsetDate.DayOfYear < birthDate.DayOfYear)
        {
              result--;
        }

        return result;
    }
}

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;

这是用一行文字回答这个问题的最简单方法。

DateTime Dob = DateTime.Parse("1985-04-24");
 
int Age = DateTime.MinValue.AddDays(DateTime.Now.Subtract(Dob).TotalHours/24 - 1).Year - 1;

这也适用于闰年。

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);

public string GetAge(this DateTime birthdate, string ageStrinFormat = null)
{
    var date = DateTime.Now.AddMonths(-birthdate.Month).AddDays(-birthdate.Day);
    return string.Format(ageStrinFormat ?? "{0}/{1}/{2}",
        (date.Year - birthdate.Year), date.Month, date.Day);
}