C# 接口的综合例子

using System;
namespace Duck
{
    interface IFly//interface接口
    {
        void Fly();

        //void FlyTwo();
    }
    interface IFlyTwo:IFly//继承接口
    {
        void FlyTwo();

        //void FlyTwo();
    }

    interface IFlyThree : IFlyTwo,IFly//继承多个接口
    {
        //void FlyTwo();
    }
    abstract class DK
    {
        /// <summary>
        ///抽象类里面只能是方法、属性、字段
        /// </summary>
        public  string id;
        public  string color;
        public  float weight;

        public abstract void Quack();
        public abstract void Swimming();
    }
    class Duck : DK
    {
        public override void Quack()
        {
            Console.WriteLine("嘎嘎嘎");
        }
        public override void Swimming()
        {
            Console.WriteLine("游啊游");
        }
        public Duck(string _id, string _color, float _weight)
        {
            this.id = _id;
            this.color = _color;
            this.weight = _weight;
        }
    }
    class FlyDuck : DK, IFlyThree//必须实现？

    {
        public override void Quack()
        {
            Console.WriteLine("嘎嘎嘎");
        }
        public override void Swimming()
        {
            Console.WriteLine("游啊游");
        }
        public void Fly()
        {
            Console.WriteLine("飞啊飞 ");
        }

        public void FlyTwo()
        {
            Console.WriteLine("飞啊飞 ");
        }
        public FlyDuck(string _id, string _color, float _weight)
        {
            this.id = _id;
            this.color = _color;
            this.weight = _weight;
        }
    }
    class Program
    {
        [STAThread]
        static void Main(string[] args)
        {
            DK[] dks = new DK[100];
            for (int i = 0; i < dks.Length; i++)
            {
                //初始化鸭子数组，数据在使用前要初始化
                dks[i] = new Duck("0", "0", 0.0f);
            }
            dks[0] = new Duck("A01", "DK1", 1.2f);
            dks[1] = new FlyDuck("A02", "DK1", 1.2f);
            dks[2] = new Duck("A03", "DK1", 1.2f);
            dks[3] = new FlyDuck("A04", "DK1", 1.2f);
            dks[4] = new Duck("A05", "DK1", 1.2f);
            dks[5] = new Duck("A06", "DK6", 1.2f);
            foreach (DK it in dks)
            {
                //让会飞的鸭子飞
                if (it is FlyDuck)
                {
                    //Console.WriteLine(it.id);                     
                    ((IFly)it).Fly();
                }

                //if (it is Duck)                {
                //    Console.WriteLine(it.id);                
                //}
            }
            Console.ReadLine();
        }
    }
}