'Contact'不包含带3个参数的构造函数 [英] 'Contact' does not contain a constructor that takes 3 arguments

问题描述

您好！我正在尝试制作电话簿程序。我希望通过以下行添加联系人：

Hello! I'm trying to make a phonebook program. I want to add a contact by this line:

Contact person = new Contact("Bob", "Smith", "0500399");

问题是我收到错误说

The problem is that I get an error saying

'Contact' does not contain a constructor that takes 3 arguments

我的'联系'课程如下：

My 'Contact' class looks like this:

class Contact
    {
        public string FristName { get; private set; }
        public string LastName  { get; private set; }
        public string PhoneNr   { get; private set; }

        public void CreateContact (string firstname, string lastname, string phonenr)
        {
            this.FristName = firstname;
            this.LastName = lastname;
            this.PhoneNr = phonenr;
        }
    }

我知道我可以通过这样做来设置这些值

I know that I could set these values by doing

person.CreateContact("Bob", "Smith", "0500399")

这不是我想要的。我想在制作实例的同时添加它。



我是编程的新手，所以请耐心等待。提前谢谢： - ）

This is not what I want. I want to add it the same time I make the instance.

I'm new to programming, so please bear with me. Thank you in advance :-)

推荐答案

为什么不让类的构造函数获取参数：

Why don't you just make the Constructor of the Class take parameters:

public Contact(string firstname, string lastname, string phonenr)
{
    this.FristName = firstname;
    this.LastName = lastname;
    this.PhoneNr = phonenr;
}

当然，如果你这样做，你真的不需要单独的'CreateContact方法。



如果你期望某些联系人没有电话号码，您可以将该参数设为可选：

Of course, if you do that, you really don't need a separate 'CreateContact method.

If you expect that some contacts will not have a phone number, you can make that parameter optional:

public Contact(string firstname, string lastname, string phonenr = "")
{
    this.FristName = firstname;
    this.LastName = lastname;
    this.PhoneNr = phonenr;
}

要稍微修复Bills代码（他实际上没有添加构造函数！），你的Contact类看起来会更像这样：

To fix Bills code a bit (he didn't actually add a constructor!), your Contact class would look more like this:

public class Contact
{
    public string FirstName { get; private set; }
    public string LastName  { get; private set; }
    public string PhoneNr   { get; private set; }

    // A public constructor
    public Contact(string firstName, string lastName, string phoneNr)
    {
        this.FirstName = firstName;
        this.LastName = lastName;
        this.PhoneNr = phoneNr;
    }

    // CreateContact should return a new Contact object.
    // That's what Create... implies.
    // You'd use it like this:
    //     Contact myContact = Contact.CreateContact(f, l, p);
    public static Contact CreateContact(string firstName, string lastName, string phoneNr)
    {
        Contact newContact = new Contact(firstname, lastname, phonenr);
        return newContact;
    }
}

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