在初始化中得到并设置误解：Jeffrey Richter,CLR通过C#

概述我刚刚在Jeffrey Richter的书(CLR通过C#4.0,第257页)发现我的代码,并误解了为什么它的工作原理. public sealed class Classroom { private List<String> m_students = new List<String>(); public List<String> Students { ge 我刚刚在Jeffrey Richter的书(CLR通过C#4.0,第257页)发现我的代码,并误解了为什么它的工作原理.

public sealed class Classroom    {        private List<String> m_students = new List<String>();        public List<String> Students { get { return m_students; } }        public Classroom() { }    }    class Program    {        static voID Main(string[] args)        {            Classroom classroom = new Classroom {                Students = { "Jeff","Kristin" }            };            foreach (var student in classroom.Students)                Console.Writeline(student);        }    }

结果：

JeffKristin

正如你所看到的,我们有一个名为“学生”的访问器属性,它只有getter(不是setter！),而是在’Main’函数中,当我们要初始化’classroom’变量时,我们初始化’Students’字段“课堂”类型：

Classroom classroom = new Classroom {    Students = { "Jeff","Kristin" }};

我一直以为,当表达式(int i = 1)的“左侧”中的变量,然后编译器应该访问setter函数,并且在“right-sIDe”(int x = i 2)到getter函数时.

为什么在杰弗里的代码中这么有趣的行为(可能只是对我来说,对不起,如果是这样).

解决方法 从C#5规范的7.6.10.2部分：

A member initializer that specifIEs a collection initializer after the equals sign is an initialization of an embedded collection. Instead of assigning a new collection to the fIEld or property,the elements given in the initializer are added to the collection referenced by the fIEld or property. The fIEld or property must be of a collection type that satisfIEs the requirements specifIEd in §7.6.10.3.

所以这段代码：

Classroom classroom = new Classroom {    Students = { "Jeff","Kristin" }};

相当于：

Classroom tmp = new Classroom();tmp.Students.Add("Jeff");tmp.Students.Add("Kristin");Classroom classroom = tmp;

基本上,对象初始化器中的=与独立赋值语句不完全相同.

编辑：这段代码

Classroom classroom = new Classroom {    Students = new List<string> { "Jeff","Kristin" }};

将无法编译,因为这将尝试为学生调用setter.

总结

以上是内存溢出为你收集整理的在初始化中得到并设置误解：Jeffrey Richter,CLR通过C#全部内容，希望文章能够帮你解决在初始化中得到并设置误解：Jeffrey Richter,CLR通过C#所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。