外观模式（Facade Pattern）

      外观模式在生活中的例子处处都在，代码中也处处在用。它将自己最简洁的面貌展示给客户程序调用，有点金玉其外，“复杂”其中的意思。
      下面用汽车启动为例，当我们扣动车钥匙发动车时，汽车内部进行了一系列的操作来发动引擎。

    public class App
    {
        public static void Main()
        {
            Car car = new Car();
            car.Run();
            car.Stop();

            Console.ReadLine();
        }
    }

    internal class Enginee
    {
        public void Open()
        {
            Console.WriteLine("引擎启动");
        }

        public void Close()
        {
            Console.WriteLine("引擎关闭");
        }
    }

    internal class Carburettor
    {
        public void Open()
        {
            Console.WriteLine("化油器加油");
        }

        public void Close()
        {
            Console.WriteLine("化油器停止加油");
        }
    }

    internal class Firedevice
    {
        public void Open()
        {
            Console.WriteLine("起火器点火");
        }

        public void Close()
        {
            Console.WriteLine("起火器关闭");
        }
    }

    public class Car
    {
        Firedevice fire;
        Carburettor burettor;
        Enginee enginee;

        public Car()
        {
            fire = new Firedevice();
            burettor = new Carburettor();
            enginee = new Enginee();
        }

        public void Run()
        {
            fire.Open();
            burettor.Open();
            enginee.Open();
            //.
            fire.Close();
            Console.WriteLine("车已启动");
        }

        public void Stop()
        {
            burettor.Close();
            enginee.Close();
            Console.WriteLine("车已停止");
        }
    }