外观模式

    interface Shape
    {
        void Draw();
    }
    public class Rectangle : Shape
    {
        public void Draw()
        {
            Console.WriteLine("矩形");
        }
    }
    public class Circle : Shape
    {
        public void Draw()
        {
            Console.WriteLine("圆形");
        }
    }

    /// <summary>
    /// 外观类，它需要了解所有的子系统的方法和属性，进行组合，以备外界调用
    /// </summary>
    public class ShapeMaker {
        private Circle circle;
        private Rectangle rectangle;
        public ShapeMaker()
        {
            circle = new Circle();
            rectangle = new Rectangle();
        }
        public void DrawCircle()
        {
            circle.Draw();
        }
        public void DrawRectangle()
        {
            rectangle.Draw();
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            ShapeMaker shapeMaker = new ShapeMaker();

            shapeMaker.DrawCircle();
            shapeMaker.DrawRectangle();
        }
    }