自定义转换

显示转换：static explicit operator

隐式转换：static implicit operator

internal class Program
    {
        static void Main(string[] args)
        {
            //基础转换
            int a = 1; float b = a; 
            int c = 'c';//char类型可以隐式转换成对应的ASCII码           
            int d =Convert.ToInt32(null); //显示
            Console.WriteLine($"{a},{b},{c},{d}");
            //自定义转换
            Dog dog = new Dog("阿黄");
            dog.Speak();
            Cat cat = (Cat)dog;//显示
            cat.Speak();
            dog = new Cat("咪咪");////隐式
            dog.Speak();
            Console.ReadKey();
        }
    }

    abstract public class Animal
    {
        public string _name = "";
        public Animal(string name)
        {
            this._name = name;
        }
        abstract public void Speak();
    }
    public class Dog : Animal
    {
        public Dog(string name) : base(name)
        {
        }
        public override void Speak()
        {
            Console.WriteLine($"汪汪！我的名字叫{_name}");
        }       
        //传入的参数是要转换的实例，而操作符类型是转换后的实例
        public static implicit operator Dog(Cat cat)
        {
            return new Dog(cat._name);
        }
    }
    public class Cat:Animal
    {
        public Cat(string name) : base(name)
        {
        }
        public override void Speak()
        {
            Console.WriteLine($"喵喵！我的名字叫{_name}");
        }
        public static explicit operator Cat(Dog dog)
        {
            return new Cat(dog._name);
        }
    }