2023-06-02 09:00:01

{get;设置;}语法在c# ?

我正在学习ASP。NET MVC和我可以阅读英文文档,但我真的不明白这段代码中发生了什么:

public class Genre
{
    public string Name { get; set; }
}

这意味着什么:{get;设置;} ?


当前回答

它基本上是一种速记。你可以写公共字符串Name {get;设置;}就像在许多例子中一样,但你也可以这样写:

private string _name;

public string Name
{
    get { return _name; }
    set { _name = value ; } // value is a special keyword here
}

为什么使用它?它可以用来过滤对属性的访问,例如您不希望名称中包含数字。

让我给你们举个例子:

private class Person {
    private int _age;  // Person._age = 25; will throw an error
    public int Age{
        get { return _age; }  // example: Console.WriteLine(Person.Age);
        set { 
            if ( value >= 0) {
                _age = value; }  // valid example: Person.Age = 25;
        }
    }
}

它的官方名称是Auto-Implemented Properties,阅读(编程指南)是一个好习惯。 我还推荐教程视频c#属性:为什么使用“get”和“set”。

其他回答

它基本上是一种速记。你可以写公共字符串Name {get;设置;}就像在许多例子中一样,但你也可以这样写:

private string _name;

public string Name
{
    get { return _name; }
    set { _name = value ; } // value is a special keyword here
}

为什么使用它?它可以用来过滤对属性的访问,例如您不希望名称中包含数字。

让我给你们举个例子:

private class Person {
    private int _age;  // Person._age = 25; will throw an error
    public int Age{
        get { return _age; }  // example: Console.WriteLine(Person.Age);
        set { 
            if ( value >= 0) {
                _age = value; }  // valid example: Person.Age = 25;
        }
    }
}

它的官方名称是Auto-Implemented Properties,阅读(编程指南)是一个好习惯。 我还推荐教程视频c#属性:为什么使用“get”和“set”。

The get/set pattern provides a structure that allows logic to be added during the setting ('set') or retrieval ('get') of a property instance of an instantiated class, which can be useful when some instantiation logic is required for the property. A property can have a 'get' accessor only, which is done in order to make that property read-only When implementing a get/set pattern, an intermediate variable is used as a container into which a value can be placed and a value extracted. The intermediate variable is usually prefixed with an underscore. this intermediate variable is private in order to ensure that it can only be accessed via its get/set calls. See the answer from Brandon, as his answer demonstrates the most commonly used syntax conventions for implementing get/set.

这是做这件事的简短方式:

public class Genre
{
    private string _name;

    public string Name
    {
      get => _name;
      set => _name = value;
    }
}

这意味着,如果您创建类型为Genre的变量,您将能够将该变量作为属性访问

Genre oG = new Genre();
oG.Name = "Test";

基本上它有助于保护你的数据。考虑这个没有setter和getter的例子,以及有它们的同一个例子。

没有setter和getter

类学生

using System;
using System.Collections.Generic;
using System.Text;

namespace MyFirstProject
{
    class Student
    {
        public string name;
        public string gender;
        public Student(string cName, string cGender)
        {
            name = cName;
            gender= cGender;
        }

     }
}

在主

 Student s = new Student("Some name", "Superman"); //Gender is superman, It works but it is meaningless
 Console.WriteLine(s.Gender);

使用setter和getter

using System;
using System.Collections.Generic;
using System.Text;

namespace MyFirstProject
{
    class Student
    {
        public string name;
        private string gender;
        public Student(string cName, string cGender)
        {
            name = cName;
            Gender = cGender;
        }

        public string Gender
        {
            get { return gender; }
            set
            {
                if (value == "Male" || value == "Female" || value == "Other")
                {
                    gender = value;
                }
                else
                {
                    throw new ArgumentException("Invalid value supplied");
                }
            }
        }
    }
}

主要:

  Student s = new Student("somename", "Other"); // Here you can set only those three values otherwise it throws ArgumentException.
Console.WriteLine(s.Gender);