如何初始化构造一个列表？ [英] How to initialize a list with constructor?

问题描述

我有一个类型：

public  class Human
{
    public int Id { get; set; }
    public string Address { get; set; }
    public string Name { get; set; }
    public List<ContactNumber> ContactNumbers { get; set; }

    public Human(int id)
    {
        Id = id;
    }

    public Human(int id, string address, string name,
                 List<ContactNumber> contactNumbers) :
        this(id)
    {
        Address = address;
        Name = name;
        ContactNumbers = contactNumbers;
    }        
}

请指引我是其中的最佳实践使用的构造与列表初始化？ 如何使用构造函数初始化列表？

Please guide me is among best practices to use constructor with for list initialization? How to initialize a list using constructor?

编辑：

请指引我是其中的最佳实践使用的构造与列表初始化？ 如何分配值使用构造函数，因此，如果没有值传递一个默认列表将被使用？

Please guide me is among best practices to use constructor with for list initialization? How to assign values to list using a constructor, so if no value passed a default will be used?

感谢

推荐答案

使用集合初始化

从C＃3，您可以使用集合初始化构造一个列表，并使用单一的前pression填充它。下面的例子中构造了一个人类及其ContactNumbers：

From C# 3, you can use collection initializers to construct a List and populate it using a single expression. The following example constructs a Human and its ContactNumbers:

var human = new Human(1, "Address", "Name") {
    ContactNumbers = new List<ContactNumber>() {
        new ContactNumber(1),
        new ContactNumber(2),
        new ContactNumber(3)
    }
}

专业的人构造

Specializing the Human constructor

您可以修改人类的构造函数提供一种方式来填充 ContactNumbers 属性：

You can change the constructor of the Human class to provide a way to populate the ContactNumbers property:

public class Human
{
    public Human(int id, string address, string name, IEnumerable<ContactNumber> contactNumbers) : this(id, address, name)
    {
        ContactNumbers = new List<ContactNumber>(contactNumbers);
    }

    public Human(int id, string address, string name, params ContactNumber[] contactNumbers) : this(id, address, name)
    {
        ContactNumbers = new List<ContactNumber>(contactNumbers);
    }
}

// Using the first constructor:
List<ContactNumber> numbers = List<ContactNumber>() {
    new ContactNumber(1),
    new ContactNumber(2),
    new ContactNumber(3)
};

var human = new Human(1, "Address", "Name", numbers);

// Using the second constructor:
var human = new Human(1, "Address", "Name",
    new ContactNumber(1),
    new ContactNumber(2),
    new ContactNumber(3)
);

底线

哪个选择是最好的做法？或者至少是一个好的做法呢？你判断它！国际海事组织，最好的做法是写程序尽可能明确地向任何人谁也读它。使用集合初始化是一个胜利者对我来说，在这种情况下。用少得多的code，它几乎可以做同样的事情作为替代品 - 至少，我给了替代品...

Which alternative is a best practice? Or at least a good practice? You judge it! IMO, the best practice is to write the program as clearly as possible to anyone who has to read it. Using the collection initializer is a winner for me, in this case. With much less code, it can do almost the same things as the alternatives -- at least, the alternatives I gave...

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