Question

假设我创建了一个名为Person的类，其中包含名称，出生年份和性别，例如：

class Person{
    public string name;
    public int year;
    public string gender;
    public Person(string _name, int _year, string _gender)
    {
        name= _name;
        year= _year;
        gender= _gender;
    }
}

使用那个班级，我在我的主人中创造了3个人，让我们说：

     Person person1 = new Person("Bob",1992,"M");

     Person person2 = new Person("Gilbert", 1984, "M");

     Person persone = new Person("hank" 1989, "F");

我的问题是：是否可以创建一个方法，该方法需要一年的时间作为参数，并仅基于该方法找到一个人的年龄和姓名？

这就是我所做的，但如果只有3个人的话，那就不好了：

public string age(int ParamAge)
{
        string message = "";
        if (ParamAge == 1992)
            message = "Bob is " + (DateTime.Now.Year - ParamAge) + " years old.";
        if (ParamAge == 1984)
            message = "Gilbert is " + (DateTime.Now.Year - ParamAge) + " years old.";
        if (ParamAge == 1989)
            message = "Hank is " + (DateTime.Now.Year - ParamAge) + " years old.";
        return message;
}

Answer 1

您应该将所有Person个实例添加到List<Person>。使用linq，您可以根据标准选择一个人。

为了简单起见，我使用了您的代码：

// this is what you know, creating persons.
Person person1 = new Person("Bob","McGee",1992,"M"); // <---- NOTE?   four parameters????  (you code would not compile....)

Person person2 = new Person("Gilbert", 1984, "M");

Person persone = new Person("hank" 1989, "F");

// create a list that contains Persons
List<Person> list = new List<Person>();

// add those persons to the list.
list.Add(person1);
list.Add(person2);
list.Add(persone);

// with the FirstOrDefault() extension method you can select a person.
Person person = personList.FirstOrDefault(item => item.year == year);

// create a message
string message;

// check if the person is a valid instance, because FirstOrDefault will return the default(Person) if none of the persons mathes the criteria. (default == null)
if(person != null)
    message = Person.name + " is " + (DateTime.Now.Year - person.year).TotalYears + " years old.";
else
    message = "Could not find anyone";

// show the message.
MessageBox.Show(message);

简而言之，您不需要为要添加的人创建一个Person声明。

例如：

list.Add(new Person("Gilbert", 1984, "M"));

Answer 2

除了对+/-一年的准确性的关注之外，我会让班级为你进行计算。

    public class Person
    {
        public string Name { get; set; }
        public int Year { get; set; }
        public string Gender { get; set; }
        public int RelativeAge
        {
            get { return  DateTime.Today.Year - Year; }
        }

        public Person(string name, int year, string gender)
        {
            Name = name;
            Year = year;
            Gender = gender;
        }

        public string AgeStatement()
        {
            return string.Format("{0} is {1} {2} old.", Name, RelativeAge, MakePlural("year", RelativeAge));
        }

        /// <summary>
        /// Add an S to values over one.
        /// </summary>
        /// <param name="element">Item to be plural</param>
        /// <param name="value"></param>
        /// <returns></returns>
        public string MakePlural(string element, int value)
        {
            return element + ((value > 1) ? "s" : "");
        }
    }

以下是验证结果的测试：

    [TestClass]
    public class PersonUnitTests
    {
        [TestMethod]
        public void TestPersonRelativeAge()
        {
            var p = new Person("Jane", 1986, "F");
            Assert.AreEqual(p.RelativeAge, 30);
        }

        [TestMethod]
        public void TestAgeStatement()
        {
            var p = new Person("Jane", 1986, "F");
            Assert.AreEqual(p.AgeStatement(), "Jane is 30 years old.");
        }
    }

根据另一个类变量

2 个答案: