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
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;
}
};
其他回答
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
}
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;
}
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。
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
);
}
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++;
}
}
推荐文章
- dynamic (c# 4)和var之间的区别是什么?
- Visual Studio: ContextSwitchDeadlock
- Sql Server字符串到日期的转换
- 返回文件在ASP。Net Core Web API
- 自定义HttpClient请求头
- 如果我使用OWIN Startup.cs类并将所有配置移动到那里,我是否需要一个Global.asax.cs文件?
- VS2013外部构建错误"error MSB4019: The imported project <path> was not found"
- 从另一个列表id中排序一个列表
- 等待一个无效的异步方法
- 无法加载文件或程序集…参数不正确
- c#中枚举中的方法
- 如何从字符串中删除新的行字符?
- 如何设置一个默认值与Html.TextBoxFor?
- 检查属性是否有属性
- 格式化XML字符串以打印友好的XML字符串