带有逻辑的c#私有Setter

本文关键字：私有 Setter | 更新日期: 2023-09-27 17:53:46

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Crystal_Message
{
    class Person
    {
        private string firstName="";
        private string lastName= "";
        private string phone="";

        public Person(string firstName, string lastName, string phone)
        {
            this.FirstName = firstName;
            this.LastName = lastName;
            this.PhoneNumber = phone;

        }
        public string FirstName
        {
            get { return firstName; }
            set
            {
                if (string.IsNullOrWhiteSpace(this.firstName)){
                    throw new ArgumentNullException("Must Include First Name");
                }
                this.firstName = value;
            }
        }
        public string LastName
        {
            get { return lastName; }
            set
            {
                if (string.IsNullOrWhiteSpace(lastName)){
                    throw new ArgumentNullException("Must Include Last Name");
                }
                this.lastName = value;
            }
        }
        public string PhoneNumber
        {
            get { return phone; }
            set
            {
                if (string.IsNullOrWhiteSpace(phone)){
                    throw new ArgumentNullException("Must Include Phone Number");
                }
                this.phone = value;
            }
        }

        public override string ToString()
        {
            return "First Name: " + this.FirstName + " " + " Last Name: " + this.LastName + " Phone Number: " + this.PhoneNumber;
        }

    }
}

我有一个简单的person类，它接受名字、姓氏和电子邮件。它对我有效，它不会被子类化。我正在构建一个小应用程序，person类是合适的。

我唯一的问题是，我如何实现一个私有 setter与内部逻辑，以确保值不是null或空?

带有逻辑的c#私有Setter

只设置setter为私有。此外，您还有一个问题:

string.IsNullOrWhiteSpace(lastName)

将读取现有的属性值。您应该检查新提供的value:

string.IsNullOrWhiteSpace(value)
最终代码:

    public string LastName
    {
        get { return lastName; }
        private set
        {
            if (string.IsNullOrWhiteSpace(value)) {
                throw new ArgumentNullException("Must Include Last Name");
            }
            lastName = value;
        }
    }

您可以为您的属性设置器使用私有修饰符:

public string FirstName
{
    get { return firstName; }
    private set
    {
        // Here you must check if value is not null or empty, not the field
        if (string.IsNullOrWhiteSpace(value)){
            throw new ArgumentNullException("Must Include First Name");
        }
        this.firstName = value;
    }
}

在这种情况下，属性的setter将只能从同一个类访问。

有两种方法:

首先，您可以去掉set，然后您的类可以对底层值进行操作:

public string FirstName
    {
        get { return firstName; }
    }
}
// Then in your code:
this.firstName = "whatever"; // the local variable

或者您可以将setter的范围设置为private:

public string FirstName
    {
        get { return firstName; }
        private set
        {
            if (string.IsNullOrWhiteSpace(this.firstName)){
                throw new ArgumentNullException("Must Include First Name");
            }
            this.firstName = value;
        }
    }
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