如何根据生日来计算年龄？

Question

可能重复：
How do I calculate someone’s age in C#?

我想写返回给他或她的生日一个人的年龄的ASP.NET的辅助方法。

我已经试过这样的代码：

public static string Age(this HtmlHelper helper, DateTime birthday) 
{ 
    return (DateTime.Now - birthday); //?? 
} 

但它不工作。根据生日计算人的年龄的正确方法是什么？

Answer 1

Stackoverflow使用这样的函数来确定用户的年龄。

Calculate age in C#

给出的答案是

DateTime now = DateTime.Today; 
int age = now.Year - bday.Year; 
if (now < bday.AddYears(age)) age--; 

所以，你的helper方法看起来像

public static string Age(this HtmlHelper helper, DateTime birthday) 
{ 
    DateTime now = DateTime.Today; 
    int age = now.Year - birthday.Year; 
    if (now < birthday.AddYears(age)) age--; 

    return age.ToString(); 
} 

今天，我用的是不同版本的功能，包括基准日期。这使我可以在未来或过去获得某人的年龄。这用于我们的预订系统，需要将来的年龄。

public static int GetAge(DateTime reference, DateTime birthday) 
{ 
    int age = reference.Year - birthday.Year; 
    if (reference < birthday.AddYears(age)) age--; 

    return age; 
} 

Answer 2

我真的不明白你为什么要把这个HTML Helper。我将它作为控制器的操作方法中的ViewData字典的一部分。类似这样的：

ViewData["Age"] = DateTime.Now.Year - birthday.Year; 

鉴于生日是传递给一个操作方法并且是一个DateTime对象。

Answer 3

我不喜欢这样写道：

（缩短了代码位）

public struct Age 
{ 
    public readonly int Years; 
    public readonly int Months; 
    public readonly int Days; 

} 

public Age(int y, int m, int d) : this() 
{ 
    Years = y; 
    Months = m; 
    Days = d; 
} 

public static Age CalculateAge (DateTime birthDate, DateTime anotherDate) 
{ 
    if(startDate.Date > endDate.Date) 
     { 
      throw new ArgumentException ("startDate cannot be higher then endDate", "startDate"); 
     } 

     int years = endDate.Year - startDate.Year; 
     int months = 0; 
     int days = 0; 

     // Check if the last year, was a full year. 
     if(endDate < startDate.AddYears (years) && years != 0) 
     { 
      years--; 
     } 

     // Calculate the number of months. 
     startDate = startDate.AddYears (years); 

     if(startDate.Year == endDate.Year) 
     { 
      months = endDate.Month - startDate.Month; 
     } 
     else 
     { 
      months = (12 - startDate.Month) + endDate.Month; 
     } 

     // Check if last month was a complete month. 
     if(endDate < startDate.AddMonths (months) && months != 0) 
     { 
      months--; 
     } 

     // Calculate the number of days. 
     startDate = startDate.AddMonths (months); 

     days = (endDate - startDate).Days; 

     return new Age (years, months, days); 
} 

// Implement Equals, GetHashCode, etc... as well 
// Overload equality and other operators, etc... 

}

Answer 4

从ancient thread另一种巧妙的方式：

int age = (
    Int32.Parse(DateTime.Today.ToString("yyyyMMdd")) - 
    Int32.Parse(birthday.ToString("yyyyMMdd")))/10000;