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）？
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);
另一个功能，不是我做的，而是在网上找到的，并做了一些改进：
public static int GetAge(DateTime birthDate)
{
DateTime n = DateTime.Now; // To avoid a race condition around midnight
int age = n.Year - birthDate.Year;
if (n.Month < birthDate.Month || (n.Month == birthDate.Month && n.Day < birthDate.Day))
age--;
return age;
}
我只想到了两件事：来自不使用公历的国家的人呢？DateTime。我认为现在是服务器特定的文化。我对实际使用亚洲日历一无所知，我不知道是否有一种简单的方法来转换日历之间的日期，但以防万一，你想知道4660年的中国人：-）
简单易懂的解决方案。
// Save today's date.
var today = DateTime.Today;
// Calculate the age.
var age = today.Year - birthdate.Year;
// Go back to the year in which the person was born in case of a leap year
if (birthdate.Date > today.AddYears(-age)) age--;
然而，这假设你在寻找西方的时代观念，而不是使用东亚的推算法。
这是我们在这里使用的版本。它有效，而且相当简单。这与Jeff的想法相同，但我认为它更清晰一点，因为它分离了减法的逻辑，所以更容易理解。
public static int GetAge(this DateTime dateOfBirth, DateTime dateAsAt)
{
return dateAsAt.Year - dateOfBirth.Year - (dateOfBirth.DayOfYear < dateAsAt.DayOfYear ? 0 : 1);
}
如果你认为这类事情不清楚，你可以扩展三元运算符使其更清晰。
显然，这是作为DateTime上的一个扩展方法完成的，但很明显，您可以抓取一行代码来完成工作并将其放在任何位置。这里我们有另一个传入DateTime的Extension方法重载。
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;
}
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;
}
};
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";
我的建议
int age = (int) ((DateTime.Now - bday).TotalDays/365.242199);
这一年似乎在正确的日期发生了变化。（我在107岁之前进行了现场测试。）
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++;
}
}
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);
下面是一个测试片段：
DateTime bDay = new DateTime(2000, 2, 29);
DateTime now = new DateTime(2009, 2, 28);
MessageBox.Show(string.Format("Test {0} {1} {2}",
CalculateAgeWrong1(bDay, now), // outputs 9
CalculateAgeWrong2(bDay, now), // outputs 9
CalculateAgeCorrect(bDay, now), // outputs 8
CalculateAgeCorrect2(bDay, now))); // outputs 8
这里有一些方法：
public int CalculateAgeWrong1(DateTime birthDate, DateTime now)
{
return new DateTime(now.Subtract(birthDate).Ticks).Year - 1;
}
public int CalculateAgeWrong2(DateTime birthDate, DateTime now)
{
int age = now.Year - birthDate.Year;
if (now < birthDate.AddYears(age))
age--;
return age;
}
public int CalculateAgeCorrect(DateTime birthDate, DateTime now)
{
int age = now.Year - birthDate.Year;
if (now.Month < birthDate.Month || (now.Month == birthDate.Month && now.Day < birthDate.Day))
age--;
return age;
}
public int CalculateAgeCorrect2(DateTime birthDate, DateTime now)
{
int age = now.Year - birthDate.Year;
// For leap years we need this
if (birthDate > now.AddYears(-age))
age--;
// Don't use:
// if (birthDate.AddYears(age) > now)
// age--;
return age;
}
这可能会起作用：
public override bool IsValid(DateTime value)
{
_dateOfBirth = value;
var yearsOld = (double) (DateTime.Now.Subtract(_dateOfBirth).TotalDays/365);
if (yearsOld > 18)
return true;
return false;
}
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.
}
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;
}
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;
}
}
保持简单（可能是愚蠢的：）。
DateTime birth = new DateTime(1975, 09, 27, 01, 00, 00, 00);
TimeSpan ts = DateTime.Now - birth;
Console.WriteLine("You are approximately " + ts.TotalSeconds.ToString() + " seconds old.");
private int GetAge(int _year, int _month, int _day
{
DateTime yourBirthDate= new DateTime(_year, _month, _day);
DateTime todaysDateTime = DateTime.Today;
int noOfYears = todaysDateTime.Year - yourBirthDate.Year;
if (DateTime.Now.Month < yourBirthDate.Month ||
(DateTime.Now.Month == yourBirthDate.Month && DateTime.Now.Day < yourBirthDate.Day))
{
noOfYears--;
}
return noOfYears;
}
我找到的最简单的方法就是这样。它适用于美国和西欧地区。无法与其他地区通话，尤其是中国这样的地方。在最初计算年龄后，最多可额外进行4次比较。
public int AgeInYears(DateTime birthDate, DateTime referenceDate)
{
Debug.Assert(referenceDate >= birthDate,
"birth date must be on or prior to the reference date");
DateTime birth = birthDate.Date;
DateTime reference = referenceDate.Date;
int years = (reference.Year - birth.Year);
//
// an offset of -1 is applied if the birth date has
// not yet occurred in the current year.
//
if (reference.Month > birth.Month);
else if (reference.Month < birth.Month)
--years;
else // in birth month
{
if (reference.Day < birth.Day)
--years;
}
return years ;
}
我仔细查看了答案，发现没有人提及闰日出生的监管/法律影响。例如，根据维基百科，如果你在2月29日出生在不同的司法管辖区，你的非闰年生日会有所不同：
在英国和香港：这是一年中的第几天，所以第二天，3月1日是你的生日。在新西兰：这是前一天，2月28日用于驾驶执照，3月1日用于其他目的。台湾：今天是2月28日。
据我所知，在美国，法规对此事保持沉默，这取决于普通法以及各个监管机构如何在其法规中定义事物。
为此，需要改进：
public enum LeapDayRule
{
OrdinalDay = 1 ,
LastDayOfMonth = 2 ,
}
static int ComputeAgeInYears(DateTime birth, DateTime reference, LeapYearBirthdayRule ruleInEffect)
{
bool isLeapYearBirthday = CultureInfo.CurrentCulture.Calendar.IsLeapDay(birth.Year, birth.Month, birth.Day);
DateTime cutoff;
if (isLeapYearBirthday && !DateTime.IsLeapYear(reference.Year))
{
switch (ruleInEffect)
{
case LeapDayRule.OrdinalDay:
cutoff = new DateTime(reference.Year, 1, 1)
.AddDays(birth.DayOfYear - 1);
break;
case LeapDayRule.LastDayOfMonth:
cutoff = new DateTime(reference.Year, birth.Month, 1)
.AddMonths(1)
.AddDays(-1);
break;
default:
throw new InvalidOperationException();
}
}
else
{
cutoff = new DateTime(reference.Year, birth.Month, birth.Day);
}
int age = (reference.Year - birth.Year) + (reference >= cutoff ? 0 : -1);
return age < 0 ? 0 : age;
}
需要注意的是，该代码假设：
西方（欧洲）对年龄的推算，以及一种日历，如公历，在月底插入一个闰日。
对此的简单答案是应用AddYears，如下所示，因为这是唯一一种将年份添加到闰年2月29日的本地方法，并获得普通年份2月28日的正确结果。
有些人认为3月1日是勒普林斯的生日，但.Net和任何官方规则都不支持这一点，也没有常见的逻辑解释为什么一些出生在2月的人应该在另一个月拥有75%的生日。
此外，Age方法可以作为DateTime的扩展添加。由此，您可以以最简单的方式获得年龄：
列表项目
int age=出生日期.age（）；
public static class DateTimeExtensions
{
/// <summary>
/// Calculates the age in years of the current System.DateTime object today.
/// </summary>
/// <param name="birthDate">The date of birth</param>
/// <returns>Age in years today. 0 is returned for a future date of birth.</returns>
public static int Age(this DateTime birthDate)
{
return Age(birthDate, DateTime.Today);
}
/// <summary>
/// Calculates the age in years of the current System.DateTime object on a later date.
/// </summary>
/// <param name="birthDate">The date of birth</param>
/// <param name="laterDate">The date on which to calculate the age.</param>
/// <returns>Age in years on a later day. 0 is returned as minimum.</returns>
public static int Age(this DateTime birthDate, DateTime laterDate)
{
int age;
age = laterDate.Year - birthDate.Year;
if (age > 0)
{
age -= Convert.ToInt32(laterDate.Date < birthDate.Date.AddYears(age));
}
else
{
age = 0;
}
return age;
}
}
现在，运行此测试：
class Program
{
static void Main(string[] args)
{
RunTest();
}
private static void RunTest()
{
DateTime birthDate = new DateTime(2000, 2, 28);
DateTime laterDate = new DateTime(2011, 2, 27);
string iso = "yyyy-MM-dd";
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
Console.WriteLine("Birth date: " + birthDate.AddDays(i).ToString(iso) + " Later date: " + laterDate.AddDays(j).ToString(iso) + " Age: " + birthDate.AddDays(i).Age(laterDate.AddDays(j)).ToString());
}
}
Console.ReadKey();
}
}
关键日期示例如下：
出生日期：2000-02-29出生日期：2011-02-28年龄：11
输出：
{
Birth date: 2000-02-28 Later date: 2011-02-27 Age: 10
Birth date: 2000-02-28 Later date: 2011-02-28 Age: 11
Birth date: 2000-02-28 Later date: 2011-03-01 Age: 11
Birth date: 2000-02-29 Later date: 2011-02-27 Age: 10
Birth date: 2000-02-29 Later date: 2011-02-28 Age: 11
Birth date: 2000-02-29 Later date: 2011-03-01 Age: 11
Birth date: 2000-03-01 Later date: 2011-02-27 Age: 10
Birth date: 2000-03-01 Later date: 2011-02-28 Age: 10
Birth date: 2000-03-01 Later date: 2011-03-01 Age: 11
}
2012年2月28日晚些时候：
{
Birth date: 2000-02-28 Later date: 2012-02-28 Age: 12
Birth date: 2000-02-28 Later date: 2012-02-29 Age: 12
Birth date: 2000-02-28 Later date: 2012-03-01 Age: 12
Birth date: 2000-02-29 Later date: 2012-02-28 Age: 11
Birth date: 2000-02-29 Later date: 2012-02-29 Age: 12
Birth date: 2000-02-29 Later date: 2012-03-01 Age: 12
Birth date: 2000-03-01 Later date: 2012-02-28 Age: 11
Birth date: 2000-03-01 Later date: 2012-02-29 Age: 11
Birth date: 2000-03-01 Later date: 2012-03-01 Age: 12
}
这个解决方案怎么样？
static string CalcAge(DateTime birthDay)
{
DateTime currentDate = DateTime.Now;
int approximateAge = currentDate.Year - birthDay.Year;
int daysToNextBirthDay = (birthDay.Month * 30 + birthDay.Day) -
(currentDate.Month * 30 + currentDate.Day) ;
if (approximateAge == 0 || approximateAge == 1)
{
int month = Math.Abs(daysToNextBirthDay / 30);
int days = Math.Abs(daysToNextBirthDay % 30);
if (month == 0)
return "Your age is: " + daysToNextBirthDay + " days";
return "Your age is: " + month + " months and " + days + " days"; ;
}
if (daysToNextBirthDay > 0)
return "Your age is: " + --approximateAge + " Years";
return "Your age is: " + approximateAge + " Years"; ;
}
2需要解决的主要问题有：
1.计算准确年龄-以年、月、日等为单位。
2.计算人们普遍认为的年龄——人们通常不关心自己到底多大，他们只关心自己当年的生日是什么时候。
1的解决方案显而易见：
DateTime birth = DateTime.Parse("1.1.2000");
DateTime today = DateTime.Today; //we usually don't care about birth time
TimeSpan age = today - birth; //.NET FCL should guarantee this as precise
double ageInDays = age.TotalDays; //total number of days ... also precise
double daysInYear = 365.2425; //statistical value for 400 years
double ageInYears = ageInDays / daysInYear; //can be shifted ... not so precise
2的解决方案在确定总年龄时并不那么精确，但人们认为它是精确的。当人们“手动”计算年龄时，通常也会使用它：
DateTime birth = DateTime.Parse("1.1.2000");
DateTime today = DateTime.Today;
int age = today.Year - birth.Year; //people perceive their age in years
if (today.Month < birth.Month ||
((today.Month == birth.Month) && (today.Day < birth.Day)))
{
age--; //birthday in current year not yet reached, we are 1 year younger ;)
//+ no birthday for 29.2. guys ... sorry, just wrong date for birth
}
注释2.：
这是我的首选解决方案我们不能使用DateTime.DayOfYear或TimeSpans，因为它们会在闰年中改变天数为了可读性，我只增加了几行
还有一个提示。。。我将为它创建两个静态重载方法，一个用于通用，另一个用于使用友好：
public static int GetAge(DateTime bithDay, DateTime today)
{
//chosen solution method body
}
public static int GetAge(DateTime birthDay)
{
return GetAge(birthDay, DateTime.Now);
}
以下方法（从.NET类DateDiff的时间段库中提取）考虑区域性信息的日历：
// ----------------------------------------------------------------------
private static int YearDiff( DateTime date1, DateTime date2 )
{
return YearDiff( date1, date2, DateTimeFormatInfo.CurrentInfo.Calendar );
} // YearDiff
// ----------------------------------------------------------------------
private static int YearDiff( DateTime date1, DateTime date2, Calendar calendar )
{
if ( date1.Equals( date2 ) )
{
return 0;
}
int year1 = calendar.GetYear( date1 );
int month1 = calendar.GetMonth( date1 );
int year2 = calendar.GetYear( date2 );
int month2 = calendar.GetMonth( date2 );
// find the the day to compare
int compareDay = date2.Day;
int compareDaysPerMonth = calendar.GetDaysInMonth( year1, month1 );
if ( compareDay > compareDaysPerMonth )
{
compareDay = compareDaysPerMonth;
}
// build the compare date
DateTime compareDate = new DateTime( year1, month2, compareDay,
date2.Hour, date2.Minute, date2.Second, date2.Millisecond );
if ( date2 > date1 )
{
if ( compareDate < date1 )
{
compareDate = compareDate.AddYears( 1 );
}
}
else
{
if ( compareDate > date1 )
{
compareDate = compareDate.AddYears( -1 );
}
}
return year2 - calendar.GetYear( compareDate );
} // YearDiff
用法：
// ----------------------------------------------------------------------
public void CalculateAgeSamples()
{
PrintAge( new DateTime( 2000, 02, 29 ), new DateTime( 2009, 02, 28 ) );
// > Birthdate=29.02.2000, Age at 28.02.2009 is 8 years
PrintAge( new DateTime( 2000, 02, 29 ), new DateTime( 2012, 02, 28 ) );
// > Birthdate=29.02.2000, Age at 28.02.2012 is 11 years
} // CalculateAgeSamples
// ----------------------------------------------------------------------
public void PrintAge( DateTime birthDate, DateTime moment )
{
Console.WriteLine( "Birthdate={0:d}, Age at {1:d} is {2} years", birthDate, moment, YearDiff( birthDate, moment ) );
} // PrintAge
这里有一个DateTime扩展程序，它将年龄计算添加到DateTime对象。
public static class AgeExtender
{
public static int GetAge(this DateTime dt)
{
int d = int.Parse(dt.ToString("yyyyMMdd"));
int t = int.Parse(DateTime.Today.ToString("yyyyMMdd"));
return (t-d)/10000;
}
}
我对Mark Soen的答案做了一个小小的修改：我重写了第三行，以便可以更容易地解析表达式。
public int AgeInYears(DateTime bday)
{
DateTime now = DateTime.Today;
int age = now.Year - bday.Year;
if (bday.AddYears(age) > now)
age--;
return age;
}
为了清晰起见，我还将其转换为函数。
我使用ScArcher2的解决方案来精确计算人的年龄，但我需要进一步计算他们的月和日以及年。
public static Dictionary<string,int> CurrentAgeInYearsMonthsDays(DateTime? ndtBirthDate, DateTime? ndtReferralDate)
{
//----------------------------------------------------------------------
// Can't determine age if we don't have a dates.
//----------------------------------------------------------------------
if (ndtBirthDate == null) return null;
if (ndtReferralDate == null) return null;
DateTime dtBirthDate = Convert.ToDateTime(ndtBirthDate);
DateTime dtReferralDate = Convert.ToDateTime(ndtReferralDate);
//----------------------------------------------------------------------
// Create our Variables
//----------------------------------------------------------------------
Dictionary<string, int> dYMD = new Dictionary<string,int>();
int iNowDate, iBirthDate, iYears, iMonths, iDays;
string sDif = "";
//----------------------------------------------------------------------
// Store off current date/time and DOB into local variables
//----------------------------------------------------------------------
iNowDate = int.Parse(dtReferralDate.ToString("yyyyMMdd"));
iBirthDate = int.Parse(dtBirthDate.ToString("yyyyMMdd"));
//----------------------------------------------------------------------
// Calculate Years
//----------------------------------------------------------------------
sDif = (iNowDate - iBirthDate).ToString();
iYears = int.Parse(sDif.Substring(0, sDif.Length - 4));
//----------------------------------------------------------------------
// Store Years in Return Value
//----------------------------------------------------------------------
dYMD.Add("Years", iYears);
//----------------------------------------------------------------------
// Calculate Months
//----------------------------------------------------------------------
if (dtBirthDate.Month > dtReferralDate.Month)
iMonths = 12 - dtBirthDate.Month + dtReferralDate.Month - 1;
else
iMonths = dtBirthDate.Month - dtReferralDate.Month;
//----------------------------------------------------------------------
// Store Months in Return Value
//----------------------------------------------------------------------
dYMD.Add("Months", iMonths);
//----------------------------------------------------------------------
// Calculate Remaining Days
//----------------------------------------------------------------------
if (dtBirthDate.Day > dtReferralDate.Day)
//Logic: Figure out the days in month previous to the current month, or the admitted month.
// Subtract the birthday from the total days which will give us how many days the person has lived since their birthdate day the previous month.
// then take the referral date and simply add the number of days the person has lived this month.
//If referral date is january, we need to go back to the following year's December to get the days in that month.
if (dtReferralDate.Month == 1)
iDays = DateTime.DaysInMonth(dtReferralDate.Year - 1, 12) - dtBirthDate.Day + dtReferralDate.Day;
else
iDays = DateTime.DaysInMonth(dtReferralDate.Year, dtReferralDate.Month - 1) - dtBirthDate.Day + dtReferralDate.Day;
else
iDays = dtReferralDate.Day - dtBirthDate.Day;
//----------------------------------------------------------------------
// Store Days in Return Value
//----------------------------------------------------------------------
dYMD.Add("Days", iDays);
return dYMD;
}
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
这很简单，似乎符合我的需要。我为闰年的目的做了一个假设，即无论一个人选择什么时候庆祝生日，从技术上讲，他们都不会比自己大一岁，直到他们的上一个生日过去365天（即2月28日不会使他们大一岁）。
DateTime now = DateTime.Today;
DateTime birthday = new DateTime(1991, 02, 03);//3rd feb
int age = now.Year - birthday.Year;
if (now.Month < birthday.Month || (now.Month == birthday.Month && now.Day < birthday.Day))//not had bday this year yet
age--;
return age;
试试这个解决方案，它奏效了。
int age = (Int32.Parse(DateTime.Today.ToString("yyyyMMdd")) -
Int32.Parse(birthday.ToString("yyyyMMdd rawrrr"))) / 10000;
这不是一个直接的答案，但更多的是从准科学的角度对当前问题进行哲学推理。
我认为，这个问题并没有具体说明衡量年龄的单位或文化，大多数答案似乎都假设了一个整数年表示。时间的国际单位制单位是秒，因此正确的通用答案应该是（当然，假设标准化日期时间，不考虑相对论效应）：
var lifeInSeconds = (DateTime.Now.Ticks - then.Ticks)/TickFactor;
在基督教以年计算年龄的方法中：
var then = ... // Then, in this case the birthday
var now = DateTime.UtcNow;
int age = now.Year - then.Year;
if (now.AddYears(-age) < then) age--;
在金融领域，当计算通常被称为日计数分数（Day Count Fraction）的东西时，也存在类似的问题，该分数大致是给定时期的年数。年龄问题确实是一个衡量时间的问题。
实际/实际（正确计算所有天数）惯例示例：
DateTime start, end = .... // Whatever, assume start is before end
double startYearContribution = 1 - (double) start.DayOfYear / (double) (DateTime.IsLeapYear(start.Year) ? 366 : 365);
double endYearContribution = (double)end.DayOfYear / (double)(DateTime.IsLeapYear(end.Year) ? 366 : 365);
double middleContribution = (double) (end.Year - start.Year - 1);
double DCF = startYearContribution + endYearContribution + middleContribution;
另一种很常见的衡量时间的方法通常是“序列化”（命名这一日期惯例的家伙一定是认真的“trippin”）：
DateTime start, end = .... // Whatever, assume start is before end
int days = (end - start).Days;
我想知道，在相对论年龄（以秒为单位）变得比迄今为止地球围绕太阳周期的粗略近似更有用之前，我们还需要多长时间：）或者换句话说，当一个周期必须给定一个位置或一个表示其自身运动的函数才能有效时：）
我们是否需要考虑小于1岁的人？作为中国文化，我们将小婴儿的年龄描述为2个月或4周。
下面是我的实现，它不像我想象的那么简单，尤其是处理2/28这样的日期。
public static string HowOld(DateTime birthday, DateTime now)
{
if (now < birthday)
throw new ArgumentOutOfRangeException("birthday must be less than now.");
TimeSpan diff = now - birthday;
int diffDays = (int)diff.TotalDays;
if (diffDays > 7)//year, month and week
{
int age = now.Year - birthday.Year;
if (birthday > now.AddYears(-age))
age--;
if (age > 0)
{
return age + (age > 1 ? " years" : " year");
}
else
{// month and week
DateTime d = birthday;
int diffMonth = 1;
while (d.AddMonths(diffMonth) <= now)
{
diffMonth++;
}
age = diffMonth-1;
if (age == 1 && d.Day > now.Day)
age--;
if (age > 0)
{
return age + (age > 1 ? " months" : " month");
}
else
{
age = diffDays / 7;
return age + (age > 1 ? " weeks" : " week");
}
}
}
else if (diffDays > 0)
{
int age = diffDays;
return age + (age > 1 ? " days" : " day");
}
else
{
int age = diffDays;
return "just born";
}
}
此实现已通过以下测试用例。
[TestMethod]
public void TestAge()
{
string age = HowOld(new DateTime(2011, 1, 1), new DateTime(2012, 11, 30));
Assert.AreEqual("1 year", age);
age = HowOld(new DateTime(2011, 11, 30), new DateTime(2012, 11, 30));
Assert.AreEqual("1 year", age);
age = HowOld(new DateTime(2001, 1, 1), new DateTime(2012, 11, 30));
Assert.AreEqual("11 years", age);
age = HowOld(new DateTime(2012, 1, 1), new DateTime(2012, 11, 30));
Assert.AreEqual("10 months", age);
age = HowOld(new DateTime(2011, 12, 1), new DateTime(2012, 11, 30));
Assert.AreEqual("11 months", age);
age = HowOld(new DateTime(2012, 10, 1), new DateTime(2012, 11, 30));
Assert.AreEqual("1 month", age);
age = HowOld(new DateTime(2008, 2, 28), new DateTime(2009, 2, 28));
Assert.AreEqual("1 year", age);
age = HowOld(new DateTime(2008, 3, 28), new DateTime(2009, 2, 28));
Assert.AreEqual("11 months", age);
age = HowOld(new DateTime(2008, 3, 28), new DateTime(2009, 3, 28));
Assert.AreEqual("1 year", age);
age = HowOld(new DateTime(2009, 1, 28), new DateTime(2009, 2, 28));
Assert.AreEqual("1 month", age);
age = HowOld(new DateTime(2009, 2, 1), new DateTime(2009, 3, 1));
Assert.AreEqual("1 month", age);
// NOTE.
// new DateTime(2008, 1, 31).AddMonths(1) == new DateTime(2009, 2, 28);
// new DateTime(2008, 1, 28).AddMonths(1) == new DateTime(2009, 2, 28);
age = HowOld(new DateTime(2009, 1, 31), new DateTime(2009, 2, 28));
Assert.AreEqual("4 weeks", age);
age = HowOld(new DateTime(2009, 2, 1), new DateTime(2009, 2, 28));
Assert.AreEqual("3 weeks", age);
age = HowOld(new DateTime(2009, 2, 1), new DateTime(2009, 3, 1));
Assert.AreEqual("1 month", age);
age = HowOld(new DateTime(2012, 11, 5), new DateTime(2012, 11, 30));
Assert.AreEqual("3 weeks", age);
age = HowOld(new DateTime(2012, 11, 1), new DateTime(2012, 11, 30));
Assert.AreEqual("4 weeks", age);
age = HowOld(new DateTime(2012, 11, 20), new DateTime(2012, 11, 30));
Assert.AreEqual("1 week", age);
age = HowOld(new DateTime(2012, 11, 25), new DateTime(2012, 11, 30));
Assert.AreEqual("5 days", age);
age = HowOld(new DateTime(2012, 11, 29), new DateTime(2012, 11, 30));
Assert.AreEqual("1 day", age);
age = HowOld(new DateTime(2012, 11, 30), new DateTime(2012, 11, 30));
Assert.AreEqual("just born", age);
age = HowOld(new DateTime(2000, 2, 29), new DateTime(2009, 2, 28));
Assert.AreEqual("8 years", age);
age = HowOld(new DateTime(2000, 2, 29), new DateTime(2009, 3, 1));
Assert.AreEqual("9 years", age);
Exception e = null;
try
{
age = HowOld(new DateTime(2012, 12, 1), new DateTime(2012, 11, 30));
}
catch (ArgumentOutOfRangeException ex)
{
e = ex;
}
Assert.IsTrue(e != null);
}
希望这有帮助。
这里有一个非常简单且易于遵循的示例。
private int CalculateAge()
{
//get birthdate
DateTime dtBirth = Convert.ToDateTime(BirthDatePicker.Value);
int byear = dtBirth.Year;
int bmonth = dtBirth.Month;
int bday = dtBirth.Day;
DateTime dtToday = DateTime.Now;
int tYear = dtToday.Year;
int tmonth = dtToday.Month;
int tday = dtToday.Day;
int age = tYear - byear;
if (bmonth < tmonth)
age--;
else if (bmonth == tmonth && bday>tday)
{
age--;
}
return age;
}
还有一个答案：
public static int AgeInYears(DateTime birthday, DateTime today)
{
return ((today.Year - birthday.Year) * 372 + (today.Month - birthday.Month) * 31 + (today.Day - birthday.Day)) / 372;
}
这已经过广泛的单元测试。它看起来确实有点“神奇”。数字372是如果每个月有31天，一年中会有多少天。
其工作原理的解释（此处省略）如下：
让我们设置Yn=DateTime.Now.Year，Yb=生日.Year，Mn=DateTime.Now.Month，Mb=生日.Month、Dn=DateTime.Now.Day，Db=生日.Day年龄=Yn-Yb+（31*（Mn-Mb）+（Dn-Db））/372我们知道，如果日期已经到达，我们需要的是Yn-Yb，如果日期尚未到达，则需要Yn-Yb-1。a） 如果Mn<Mb，我们有-341<=31*（Mn-Mb）<=-31和-30<=Dn-Db<=30-371<=31*（锰-Mb）+（Dn-Db）<=-1带整数除法（31*（Mn-Mb）+（Dn-Db））/372=-1b） 如果Mn=Mb和Dn<Db，则我们有31*（Mn-Mb）=0和-30<=Dn Db<=-1再次使用整数除法（31*（Mn-Mb）+（Dn-Db））/372=-1c） 如果Mn>Mb，我们有31<=31*（Mn-Mb）<=341和-30<=Dn-Db<=301<=31*（Mn-Mb）+（Dn-Db）<=371带整数除法（31*（Mn-Mb）+（Dn-Db））/372=0d） 如果Mn=Mb且Dn>Db，则我们有31*（Mn-Mb）=0且1<=Dn Db<=30再次使用整数除法（31*（Mn-Mb）+（Dn-Db））/372=0e） 如果Mn=Mb，Dn=Db，我们有31*（Mn-Mb）+Dn Db=0因此（31*（Mn-Mb）+（Dn-Db））/372=0
通过较少的转换和UtcNow，这段代码可以照顾闰年2月29日出生的人：
public int GetAge(DateTime DateOfBirth)
{
var Now = DateTime.UtcNow;
return Now.Year - DateOfBirth.Year -
(
(
Now.Month > DateOfBirth.Month ||
(Now.Month == DateOfBirth.Month && Now.Day >= DateOfBirth.Day)
) ? 0 : 1
);
}
MSDN帮助为什么没有告诉您这一点？看起来很明显：
System.DateTime birthTime = AskTheUser(myUser); // :-)
System.DateTime now = System.DateTime.Now;
System.TimeSpan age = now - birthTime; // As simple as that
double ageInDays = age.TotalDays; // Will you convert to whatever you want yourself?
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。
这为这个问题提供了“更多细节”。也许这就是你要找的
DateTime birth = new DateTime(1974, 8, 29);
DateTime today = DateTime.Now;
TimeSpan span = today - birth;
DateTime age = DateTime.MinValue + span;
// Make adjustment due to MinValue equalling 1/1/1
int years = age.Year - 1;
int months = age.Month - 1;
int days = age.Day - 1;
// Print out not only how many years old they are but give months and days as well
Console.Write("{0} years, {1} months, {2} days", years, months, days);
要使用最近的年龄计算年龄：
var ts = DateTime.Now - new DateTime(1988, 3, 19);
var age = Math.Round(ts.Days / 365.0);
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。
一句话的回答：
DateTime dateOfBirth = Convert.ToDateTime("01/16/1990");
var age = ((DateTime.Now - dateOfBirth).Days) / 365;
这是最准确的答案之一，它能够解决2月29日的生日，而不是2月28日的任何一年。
public int GetAge(DateTime birthDate)
{
int age = DateTime.Now.Year - birthDate.Year;
if (birthDate.DayOfYear > DateTime.Now.DayOfYear)
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;
}
看看这个：
TimeSpan ts = DateTime.Now.Subtract(Birthdate);
age = (byte)(ts.TotalDays / 365.25);
这是一个非常适合我的功能。没有计算，非常简单。
public static string ToAge(this DateTime dob, DateTime? toDate = null)
{
if (!toDate.HasValue)
toDate = DateTime.Now;
var now = toDate.Value;
if (now.CompareTo(dob) < 0)
return "Future date";
int years = now.Year - dob.Year;
int months = now.Month - dob.Month;
int days = now.Day - dob.Day;
if (days < 0)
{
months--;
days = DateTime.DaysInMonth(dob.Year, dob.Month) - dob.Day + now.Day;
}
if (months < 0)
{
years--;
months = 12 + months;
}
return string.Format("{0} year(s), {1} month(s), {2} days(s)",
years,
months,
days);
}
这里是一个单元测试：
[Test]
public void ToAgeTests()
{
var date = new DateTime(2000, 1, 1);
Assert.AreEqual("0 year(s), 0 month(s), 1 days(s)", new DateTime(1999, 12, 31).ToAge(date));
Assert.AreEqual("0 year(s), 0 month(s), 0 days(s)", new DateTime(2000, 1, 1).ToAge(date));
Assert.AreEqual("1 year(s), 0 month(s), 0 days(s)", new DateTime(1999, 1, 1).ToAge(date));
Assert.AreEqual("0 year(s), 11 month(s), 0 days(s)", new DateTime(1999, 2, 1).ToAge(date));
Assert.AreEqual("0 year(s), 10 month(s), 25 days(s)", new DateTime(1999, 2, 4).ToAge(date));
Assert.AreEqual("0 year(s), 10 month(s), 1 days(s)", new DateTime(1999, 2, 28).ToAge(date));
date = new DateTime(2000, 2, 15);
Assert.AreEqual("0 year(s), 0 month(s), 28 days(s)", new DateTime(2000, 1, 18).ToAge(date));
}
我只想这样做：
DateTime birthDay = new DateTime(1990, 05, 23);
DateTime age = DateTime.Now - birthDay;
这样你就可以计算出一个人的确切年龄，如果你愿意的话，可以精确到毫秒。
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);
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);
}
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。
==常见说法（从几个月到几岁）===
如果您只是为了通用，以下是代码作为您的信息：
DateTime today = DateTime.Today;
DateTime bday = DateTime.Parse("2016-2-14");
int age = today.Year - bday.Year;
var unit = "";
if (bday > today.AddYears(-age))
{
age--;
}
if (age == 0) // Under one year old
{
age = today.Month - bday.Month;
age = age <= 0 ? (12 + age) : age; // The next year before birthday
age = today.Day - bday.Day >= 0 ? age : --age; // Before the birthday.day
unit = "month";
}
else {
unit = "year";
}
if (age > 1)
{
unit = unit + "s";
}
测试结果如下：
The birthday: 2016-2-14
2016-2-15 => age=0, unit=month;
2016-5-13 => age=2, unit=months;
2016-5-14 => age=3, unit=months;
2016-6-13 => age=3, unit=months;
2016-6-15 => age=4, unit=months;
2017-1-13 => age=10, unit=months;
2017-1-14 => age=11, unit=months;
2017-2-13 => age=11, unit=months;
2017-2-14 => age=1, unit=year;
2017-2-15 => age=1, unit=year;
2017-3-13 => age=1, unit=year;
2018-1-13 => age=1, unit=year;
2018-1-14 => age=1, unit=year;
2018-2-13 => age=1, unit=year;
2018-2-14 => age=2, unit=years;
SQL版本：
declare @dd smalldatetime = '1980-04-01'
declare @age int = YEAR(GETDATE())-YEAR(@dd)
if (@dd> DATEADD(YYYY, -@age, GETDATE())) set @age = @age -1
print @age
哇，我不得不在这里回答。。。这么简单的问题有很多答案。
private int CalcularIdade(DateTime dtNascimento)
{
var nHoje = Convert.ToInt32(DateTime.Today.ToString("yyyyMMdd"));
var nAniversario = Convert.ToInt32(dtNascimento.ToString("yyyyMMdd"));
double diff = (nHoje - nAniversario) / 10000;
var ret = Convert.ToInt32(Math.Truncate(diff));
return ret;
}
private int GetYearDiff(DateTime start, DateTime end)
{
int diff = end.Year - start.Year;
if (end.DayOfYear < start.DayOfYear) { diff -= 1; }
return diff;
}
[Fact]
public void GetYearDiff_WhenCalls_ShouldReturnCorrectYearDiff()
{
//arrange
var now = DateTime.Now;
//act
//assert
Assert.Equal(24, GetYearDiff(new DateTime(1992, 7, 9), now)); // passed
Assert.Equal(24, GetYearDiff(new DateTime(1992, now.Month, now.Day), now)); // passed
Assert.Equal(23, GetYearDiff(new DateTime(1992, 12, 9), now)); // passed
}
我经常用手指数。我需要看一下日历，以确定事情何时发生变化。这就是我在代码中要做的：
int AgeNow(DateTime birthday)
{
return AgeAt(DateTime.Now, birthday);
}
int AgeAt(DateTime now, DateTime birthday)
{
return AgeAt(now, birthday, CultureInfo.CurrentCulture.Calendar);
}
int AgeAt(DateTime now, DateTime birthday, Calendar calendar)
{
// My age has increased on the morning of my
// birthday even though I was born in the evening.
now = now.Date;
birthday = birthday.Date;
var age = 0;
if (now <= birthday) return age; // I am zero now if I am to be born tomorrow.
while (calendar.AddYears(birthday, age + 1) <= now)
{
age++;
}
return age;
}
在LINQPad中运行此过程可获得以下结果：
PASSED: someone born on 28 February 1964 is age 4 on 28 February 1968
PASSED: someone born on 29 February 1964 is age 3 on 28 February 1968
PASSED: someone born on 31 December 2016 is age 0 on 01 January 2017
LINQPad中的代码在这里。
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 --;
只需使用：
(DateTime.Now - myDate).TotalHours / 8766.0
当前日期-myDate=TimeSpan，获取总小时数并除以每年的总小时数，得到确切的年龄/月/日。。。
以下是计算某人年龄的最简单方法。计算某人的年龄非常简单，下面是计算方法！为了使代码正常工作，您需要一个名为BirthDate的DateTime对象，该对象包含生日。
C#
// get the difference in years
int years = DateTime.Now.Year - BirthDate.Year;
// subtract another year if we're before the
// birth day in the current year
if (DateTime.Now.Month < BirthDate.Month ||
(DateTime.Now.Month == BirthDate.Month &&
DateTime.Now.Day < BirthDate.Day))
years--;
VB.NET
' get the difference in years
Dim years As Integer = DateTime.Now.Year - BirthDate.Year
' subtract another year if we're before the
' birth day in the current year
If DateTime.Now.Month < BirthDate.Month Or (DateTime.Now.Month = BirthDate.Month And DateTime.Now.Day < BirthDate.Day) Then
years = years - 1
End If
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。
非常简单的答案
DateTime dob = new DateTime(1991, 3, 4);
DateTime now = DateTime.Now;
int dobDay = dob.Day, dobMonth = dob.Month;
int add = -1;
if (dobMonth < now.Month)
{
add = 0;
}
else if (dobMonth == now.Month)
{
if(dobDay <= now.Day)
{
add = 0;
}
else
{
add = -1;
}
}
else
{
add = -1;
}
int age = now.Year - dob.Year + add;
int Age = new DateTime((DateTime.Now - BirthDate).Ticks).Year -1;
Console.WriteLine("Age {0}", Age);
我认为这个问题可以用这样一种更简单的方法解决-
该类可以是-
using System;
namespace TSA
{
class BirthDay
{
double ageDay;
public BirthDay(int day, int month, int year)
{
DateTime birthDate = new DateTime(year, month, day);
ageDay = (birthDate - DateTime.Now).TotalDays; //DateTime.UtcNow
}
internal int GetAgeYear()
{
return (int)Math.Truncate(ageDay / 365);
}
internal int GetAgeMonth()
{
return (int)Math.Truncate((ageDay % 365) / 30);
}
}
}
电话可以是这样的-
BirthDay b = new BirthDay(1,12,1990);
int year = b.GetAgeYear();
int month = b.GetAgeMonth();
我对DateTime一无所知，但我能做的就是：
using System;
public class Program
{
public static int getAge(int month, int day, int year) {
DateTime today = DateTime.Today;
int currentDay = today.Day;
int currentYear = today.Year;
int currentMonth = today.Month;
int age = 0;
if (currentMonth < month) {
age -= 1;
} else if (currentMonth == month) {
if (currentDay < day) {
age -= 1;
}
}
currentYear -= year;
age += currentYear;
return age;
}
public static void Main()
{
int ageInYears = getAge(8, 10, 2007);
Console.WriteLine(ageInYears);
}
}
有点困惑，但仔细看代码，这一切都是有意义的。
var startDate = new DateTime(2015, 04, 05);//your start date
var endDate = DateTime.Now;
var years = 0;
while(startDate < endDate)
{
startDate = startDate.AddYears(1);
if(startDate < endDate)
{
years++;
}
}
人们可以这样计算“年龄”（即“西方人”的方式）：
public static int AgeInYears(this System.DateTime source, System.DateTime target)
=> target.Year - source.Year is int age && age > 0 && source.AddYears(age) > target ? age - 1 : age < 0 && source.AddYears(age) < target ? age + 1 : age;
如果时间方向为“负”，则年龄也将为负。
可以添加一个分数，代表从目标到下一个生日的累计年龄：
public static double AgeInTotalYears(this System.DateTime source, System.DateTime target)
{
var sign = (source <= target ? 1 : -1);
var ageInYears = AgeInYears(source, target); // The method above.
var last = source.AddYears(ageInYears);
var next = source.AddYears(ageInYears + sign);
var fractionalAge = (double)(target - last).Ticks / (double)(next - last).Ticks * sign;
return ageInYears + fractionalAge;
}
分数是过去的时间（从上一个生日到下一个生日）与总时间的比率。
无论是向前还是向后，这两种方法都以相同的方式工作。
我强烈建议使用名为AgeCalculator的NuGet软件包，因为在计算年龄（闰年、时间成分等）时需要考虑很多事情，而且只有两行代码不能削减它。该库给您的时间不只是一年。它甚至在计算时考虑了时间成分，这样你就可以得到一个包含年、月、日和时间成分的准确年龄。更为先进的是，可以选择将2月29日作为闰年，而将2月28日作为非闰年。
无分支解决方案：
public int GetAge(DateOnly birthDate, DateOnly today)
{
return today.Year - birthDate.Year + (((today.Month << 5) + today.Day - ((birthDate.Month << 5) + birthDate.Day)) >> 31);
}
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;
}
不知道为什么没有人尝试过：
ushort age = (ushort)DateAndTime.DateDiff(DateInterval.Year, DateTime.Now.Date, birthdate);
它只需要使用Microsoft.VisualBasic；并引用项目中的此程序集（如果尚未引用）。
var EndDate = new DateTime(2022, 4, 21);
var StartDate = new DateTime(1986, 4, 25);
Int32 Months = EndDate.Month - StartDate.Month;
Int32 Years = EndDate.Year - StartDate.Year;
Int32 Days = EndDate.Day - StartDate.Day;
if (Days < 0)
{
Months = Months - 1;
}
if (Months < 0)
{
Years = Years - 1;
Months = Months + 12;
}
string Ages = Years.ToString() + " Year(s) " + Months.ToString() + " Month(s) ";
为什么不能简化为检查出生日期？
第一行（var year=end.year-start.year-1；）：假设出生日期尚未发生在结束年份。然后检查月份和日期，看看是否发生了；再增加一年。
对闰年情景没有特殊处理。如果不是闰年，你不能创建一个日期（2月29日）作为结束日期，所以如果结束日期是3月1日，而不是28日，生日庆祝活动将被计算在内。下面的函数将将此场景作为普通日期进行描述。
static int Get_Age(DateTime start, DateTime end)
{
var year = end.Year - start.Year - 1;
if (end.Month < start.Month)
return year;
else if (end.Month == start.Month)
{
if (end.Day >= start.Day)
return ++year;
return year;
}
else
return ++year;
}
static void Test_Get_Age()
{
var start = new DateTime(2008, 4, 10); // b-date, leap year BTY
var end = new DateTime(2023, 2, 1); // end date is before the b-date
var result1 = Get_Age(start, end);
var success1 = result1 == 14; // true
end = new DateTime(2023, 4, 10); // end date is on the b-date
var result2 = Get_Age(start, end);
var success2 = result2 == 15; // true
end = new DateTime(2023, 6, 22); // end date is after the b-date
var result3 = Get_Age(start, end);
var success3 = result3 == 15; // true
start = new DateTime(2008, 2, 29); // b-date is on feb 29
end = new DateTime(2023, 2, 28); // end date is before the b-date
var result4 = Get_Age(start, end);
var success4 = result4 == 14; // true
end = new DateTime(2020, 2, 29); // end date is on the b-date, on another leap year
var result5 = Get_Age(start, end);
var success5 = result5 == 12; // true
}
以下是使用DateTimeOffset和手动数学的答案：
var diff = DateTimeOffset.Now - dateOfBirth;
var sinceEpoch = DateTimeOffset.UnixEpoch + diff;
return sinceEpoch.Year - 1970;
