命名空间、访问修饰符、枚举、集合、静态、只读、常量

• • 命名空间
  • 访问修饰符
  • `enum`
  • 集合
  • • `List`
    • `ArrayList`
    • `Sort` 排序
    • `Hashtable`
    • `Dictionary`
  • static
  • `readonly` 和 `const`

命名空间

• 命名空间是一个虚拟的集合
• 命名空间中只能是 类 、 结构体 、 枚举 、 接口 等类型
• 命名空间防止类名重复，更好的管理类

using System;
using AAA;namespace ConsoleAppDemo
{class MainClass{public static void Main(string[] args){Person.name = "Lee"; // using AAA; 默认会去使用AAA中的PersonBBB.Person.name = "Zhang";Animal.name = "Dog"; // using AAA; 默认会去使用AAA中的Animal}}}namespace AAA {static class Person{public static string name;}static class Animal{public static string name;}
}namespace BBB
{static class Person{public static string name;}namespace CCC{static class Person{public static string name;}}
}

访问修饰符

注意：权限低的访问不了权限高的，权限低的也当不了权限高的的父类

enum

// 枚举中指定元素类型(并且只能配置成整型)及默认值
enum Weekday : int
{Sun = 0, Mon, Tue, Wed, Thu, Fri, Sat,
}internal class Program
{static void Main(string[] args){Console.WriteLine(Weekday.Sun);             // SunConsole.WriteLine(Weekday.Sun == 0);        // TrueConsole.WriteLine((int)Weekday.Sun == 0);   // TrueConsole.WriteLine(Weekday.Mon);             // Mon//Console.WriteLine(Weekday.Mon == 1);      // ErrorConsole.WriteLine((int)Weekday.Mon == 1);   // TrueConsole.WriteLine(Weekday.Tue);             // TueConsole.WriteLine((int)Weekday.Tue);        // 2Console.WriteLine(Weekday.Wed);             // WedConsole.WriteLine(Weekday.Thu);             // ThuConsole.WriteLine(Weekday.Fri);             // FriConsole.WriteLine(Weekday.Sat);             // SatWeekday weekday = Weekday.Sun;// 周日switch (weekday){case Weekday.Sun:Console.WriteLine("周日");break;case Weekday.Mon:Console.WriteLine("周一");break;case Weekday.Tue:Console.WriteLine("周二");break;case Weekday.Wed:Console.WriteLine("周三");break;case Weekday.Thu:Console.WriteLine("周四");break;case Weekday.Fri:Console.WriteLine("周五");break;case Weekday.Sat:Console.WriteLine("周六");break;}}
}

集合

class Person
{public string name;public int age;public Person(string name, int age){this.name = name;this.age = age;}
}

List

using System.Collections.Generic;internal class Program
{static void Main(string[] args){// List persons = new List();// persons.Add(new Person("Lee", 25));// persons.Add(new Person("ZhangSan", 30));List persons = new List{new Person("Lee", 25),new Person("ZhangSan", 30)};// List