这里有一个单行线：

int age = new DateTime(DateTime.Now.Subtract(birthday).Ticks).Year-1;

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;
    }
}

我在这个问题上使用了以下内容。我知道它不太优雅，但它很管用。

DateTime zeroTime = new DateTime(1, 1, 1);
var date1 = new DateTime(1983, 03, 04);
var date2 = DateTime.Now;
var dif = date2 - date1;
int years = (zeroTime + dif).Year - 1;
Log.DebugFormat("Years -->{0}", years);

我有一个定制的计算年龄的方法，加上一条奖金验证消息，以防有帮助：

public void GetAge(DateTime dob, DateTime now, out int years, out int months, out int days)
{
    years = 0;
    months = 0;
    days = 0;

    DateTime tmpdob = new DateTime(dob.Year, dob.Month, 1);
    DateTime tmpnow = new DateTime(now.Year, now.Month, 1);

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

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

    if (DateTime.IsLeapYear(dob.Year) && dob.Month == 2 && dob.Day == 29 && now >= new DateTime(now.Year, 3, 1))
        days++;

}   

private string ValidateDate(DateTime dob) //This method will validate the date
{
    int Years = 0; int Months = 0; int Days = 0;

    GetAge(dob, DateTime.Now, out Years, out Months, out Days);

    if (Years < 18)
        message =  Years + " is too young. Please try again on your 18th birthday.";
    else if (Years >= 65)
        message = Years + " is too old. Date of Birth must not be 65 or older.";
    else
        return null; //Denotes validation passed
}

方法调用此处并传递日期时间值（如果服务器设置为美国语言环境，则为MM/dd/yyyy）。将其替换为消息框或要显示的任何容器：

DateTime dob = DateTime.Parse("03/10/1982");  

string message = ValidateDate(dob);

lbldatemessage.Visible = !StringIsNullOrWhitespace(message);
lbldatemessage.Text = message ?? ""; //Ternary if message is null then default to empty string

记住，您可以按任何方式格式化邮件。

为了计算一个人的年龄，

DateTime dateOfBirth;

int ageInYears = DateTime.Now.Year - dateOfBirth.Year;

if (dateOfBirth > today.AddYears(-ageInYears )) ageInYears --;

我认为TimeSpan包含了我们所需要的一切，而不必求助于365.25（或任何其他近似值）。扩展Aug的示例：

DateTime myBD = new DateTime(1980, 10, 10);
TimeSpan difference = DateTime.Now.Subtract(myBD);

textBox1.Text = difference.Years + " years " + difference.Months + " Months " + difference.Days + " days";