给定代表某人生日的DateTime,我如何计算他们的年龄(以年为单位)?


当前回答

简单代码

 var birthYear=1993;
 var age = DateTime.Now.AddYears(-birthYear).Year;

其他回答

一句话的回答:

DateTime dateOfBirth = Convert.ToDateTime("01/16/1990");
var age = ((DateTime.Now - dateOfBirth).Days) / 365;

这是一种奇怪的方法,但如果您将日期设置为yyyymmdd,并从当前日期中减去出生日期,然后删除您获得的年龄的最后4位数字:)

我不知道C#,但我相信这在任何语言中都适用。

20080814 - 19800703 = 280111 

删除最后4位=28。

C#代码:

int now = int.Parse(DateTime.Now.ToString("yyyyMMdd"));
int dob = int.Parse(dateOfBirth.ToString("yyyyMMdd"));
int age = (now - dob) / 10000;

或者,也可以不进行扩展方法形式的所有类型转换。忽略错误检查:

public static Int32 GetAge(this DateTime dateOfBirth)
{
    var today = DateTime.Today;

    var a = (today.Year * 100 + today.Month) * 100 + today.Day;
    var b = (dateOfBirth.Year * 100 + dateOfBirth.Month) * 100 + dateOfBirth.Day;

    return (a - b) / 10000;
}

简单易读,方法互补

public static int getAge(DateTime birthDate)
{
    var today = DateTime.Today;
    var age = today.Year - birthDate.Year;
    var monthDiff = today.Month - birthDate.Month;
    var dayDiff = today.Day - birthDate.Day;

    if (dayDiff < 0)
    {
        monthDiff--;
    }
    if (monthDiff < 0)
    {
       age--;
    }
    return age;
}

只是因为我认为最重要的答案不是那么明确:

public static int GetAgeByLoop(DateTime birthday)
{
    var age = -1;

    for (var date = birthday; date < DateTime.Today; date = date.AddYears(1))
    {
        age++;
    }

    return age;
}

我想添加希伯来文日历计算(或其他系统。全球化日历可以以相同的方式使用),使用此线程中的重写函数:

Public Shared Function CalculateAge(BirthDate As DateTime) As Integer
    Dim HebCal As New System.Globalization.HebrewCalendar ()
    Dim now = DateTime.Now()
    Dim iAge = HebCal.GetYear(now) - HebCal.GetYear(BirthDate)
    Dim iNowMonth = HebCal.GetMonth(now), iBirthMonth = HebCal.GetMonth(BirthDate)
    If iNowMonth < iBirthMonth Or (iNowMonth = iBirthMonth AndAlso HebCal.GetDayOfMonth(now) < HebCal.GetDayOfMonth(BirthDate)) Then iAge -= 1
    Return iAge
End Function