05 泛型

类型约束：http://docs.manew.com/csharp/117.html

using System;
using System.Collections.Generic;
namespace FactoryModern
{
    class Program
    {
        static void Main(string[] args)
        {
            //声明加人类工厂
            AbstractHumanFactory factory = new HumanFactory();
            //第一次造白种人
            IHuman human = factory.CreateHuman<WhiteHuman>();
            human.GetColor();
            human.Talk();
            //第二次造黑人
            human = factory.CreateHuman<BlackHuman>();
            human.GetColor();
            human.Talk();
        }
    }
    public interface IHuman
    {
        void GetColor();
        void Talk();
    }
    class BlackHuman : IHuman
    {
        public void GetColor()
        {
            Console.WriteLine("My Color is black.");
        }
        public void Talk()
        {
            Console.WriteLine("My language is xxxx");
        }
    }
    class WhiteHuman : IHuman
    {
        public void GetColor()
        {
            Console.WriteLine("My Color is white.");
        }
        public void Talk()
        {
            Console.WriteLine("My language is english");
        }
    }
    class YellowHuman : IHuman
    {
        public void GetColor()
        {
            Console.WriteLine("My Color is yellow.");
        }
        public void Talk()
        {
            Console.WriteLine("My language is chinese");
        }
    }
   public abstract class AbstractHumanFactory
    {
        //where约束T为class类型，必须是来自IHuman或者是实现IHuman接口,可创建实例
        public abstract T CreateHuman<T>() where T : class,IHuman,new();      
    }
    public class HumanFactory : AbstractHumanFactory
    {
        public override T CreateHuman<T>()
        {
            IHuman human = null;
            try
            {
                human = new T();
            }
            catch
            {
                Console.WriteLine("人种生成错误");
            }
            return (T)human;
        }
    }
}