C#入门之定义类成员与接口实现

class MyClass
{
    public int MyInt;//公共字段
    int myInt;//私有字段
    public readonly int MyInt2 = 17;//只读成员，只能在声明时赋值或在构造函数中赋值。
    public static int myInt3;//静态字段，通过类访问。作用：1、记录一实例化对象的个数，2、存储必须在所有实例间共享的值。
    public const float PI = 3.14F;//常量，编译时就固定，一旦发生更改，需要重新编译，必须且只有在声明时初始化。
}

void Main()
{
    A b1 = new B();//多态
    b1.M();//BM  

    B b2 = new B();
    b2.M();//BM  
}

abstract class A
{
    public virtual void M()//虚拟方法，可继承
    {
        Console.Write("AM");
    }
}

class B : A
{
    public override void M()// 重写了基类方法M
    {
        Console.Write("BM");
    }
}

void Main()
{
    A b1 = new B();
    b1.M();//AM  

    B b2 = new B();
    b2.M();//BM  
}

abstract class A
{
    public virtual void M()//虚拟方法，可继承
    {
        Console.Write("AM");
    }
}

class B : A
{
    public new void M()// 重写了基类方法M
    {
        Console.Write("BM");
    }
}

public class A
{
    private int intVal;
    public int Val
    {
        get { return intVal; }
        set
        {
            if (value >= 0 && value <= 10)
                intVla = value;
            else
                throw new Exception("XX");
        }
    }
}

interface IMyInterface //定义接口
{
    int DoSth();//定义方法
    int IMyInt { set; get; }//定义属性
    event EventHandler Event;//定义事件
    string this[int index] { get; set; } //定义索引器
}

class MyClass : IMyInterface
{
    private int _x;

    int IMyInterface.DoSth()   //显示接口实现
    {
        return _x;
    }
    public int IMyInt//隐式接口实现
    {
        get { return _x; }
        set { _x = value; }
    }

    public event EventHandler Event;

    protected void onEvent()
    {
        if (Event == null)
        {
            Event(this, EventArgs.Empty);
        }
    }

    public string this[int index]
    {
        get { return _x.ToString(); }
        set { _x = int.Parse(value); }
    }
}

MyInterface myClass=new MyClass();
myClass.DoSth();

MyClass myClass=new MyClass();
myClass.DoSth();

void Main()
{
    MyClass myClass = new MyClass();
    myClass[0] = "d";
    Console.Write(myClass[0]);//d
    Console.Write(myClass[2]);//c
}

public class MyClass
{
    private string[] arr = { "a", "b", "c" };
    public string this[int index]
    {
        get { return arr[index]; }//只有get，无set的索引为只读索引
        set { arr[index] = value; }
    }
}

void Main()
{
    MyClass myClass1 = new MyClass(500);
    MyClass myClass2 = new MyClass(200);
    Console.Write(myClass1 - myClass2);//300
}

public class MyClass
{
    decimal weight;
    public MyClass(decimal weight)
    {
        this.weight = weight;
    }
    public static decimal operator -(MyClass a, MyClass b)
    {
        return a.weight - b.weight;
    }
}

void Main()
{
    MyClass myClass1 = new MyClass();
    myClass1.myEvent += (sender, args) => { Console.Write(sender); };
    myClass1.TriggerEvent();//MyClass

}

public class MyClass
{
    public event EventHandler<EventArgs> myEvent;//定义事件
    public void TriggerEvent()
    {
        EventHandler<EventArgs> temp = myEvent;
        if (temp != null)
            temp(this, EventArgs.Empty);//触发事件
    }
}