class Person
{
    string Name;
    DateTime BirthDate;

    //constructor
    Person(string Name,DateTime BirthDate)
    {
        this.Name = Name;
        this.BirthDate = BirthDate;
    }

    int GetAge()
    {
        return Today - BirthDate; //for illustration only
    }

}

现在,将行为和数据分离成单独的类.

class Person
{
    string Name;
    DateTime BirthDate;

    //constructor
    Person(string Name,DateTime BirthDate)
    {
        this.Name = Name;
        this.BirthDate = BirthDate;
    }
}

class PersonService
{
    Person personObject;

    //constructor
    PersonService(string Name,DateTime BirthDate)
    {
        this.personObject = new Person(Name,BirthDate);
    }

    //overloaded constructor
    PersonService(Person personObject)
    {
        this.personObject = personObject;
    }

    int GetAge()
    {
        return personObject.Today - personObject.BirthDate; //for illustration only
    }
}

这应该是有益的,并提高灵活性并提供松耦合.我看不到怎么样据我所知,这引入了额外的编码和性能损失,每次我们必须初始化两个类对象.我在扩展这个代码时看到更多的问题.考虑在上面介绍继承时会发生什么.我们必须继承这两个类

class Employee: Person
{
    Double Salary;

    Employee(string Name,DateTime BirthDate,Double Salary): base(Name,BirthDate)
    {
        this.Salary = Salary;       
    }

}

class EmployeeService: PersonService
{
    Employee employeeObject;

    //constructor
    EmployeeService(string Name,Double Salary)
    {
        this.employeeObject = new Employee(Name,BirthDate,Salary);
    }

    //overloaded constructor
    EmployeeService(Employee employeeObject)
    {
        this.employeeObject = employeeObject;
    }
}

请注意,即使我们在一个单独的类中隔离行为,我们仍然需要使用“类”类的对象来执行Behavior类方法.所以最后我们的Behavior类包含数据和行为,尽管我们有一个模型对象形式的数据.
你可以说可以添加一些接口到混合,所以我们可以有IPersonService和IEmployeeService.但是,我认为为每个类引入接口并从接口继承似乎不行.
那么那么你可以告诉我,在上述情况下,通过分开数据和行为来实现这一点,我不能通过将它们放在同一个类中来实现