# 装饰器模式

属于结构型模式，它是作为现有的类的一个包装。
装饰器模式通过将对象包装在装饰器类中，以便动态地修改其行为，提供了额外的功能。

装饰器模式包含以下几个核心角色：

装饰器模式通过嵌套包装多个装饰器对象，可以实现多层次的功能增强。每个具体装饰器类都可以选择性地增加新的功能，同时保持对象接口的一致性。

# 类图

	namespace StructuralPattern_DecoratorPattern
	{
	public interface IShape
	{
	/// <summary>
	/// 形状
	/// </summary>
	public void MyShape();
	}
	}

	namespace StructuralPattern_DecoratorPattern
	{
	/// <summary>
	/// 圆形
	/// </summary>
	public class Circle : IShape
	{
	public void MyShape()
	{
	Console.WriteLine("Circle");
	}
	}
	}

	namespace StructuralPattern_DecoratorPattern
	{
	/// <summary>
	/// 正方形
	/// </summary>
	public class Square : IShape
	{
	public void MyShape()
	{
	Console.WriteLine("Square");
	}
	}
	}

	namespace StructuralPattern_DecoratorPattern
	{
	/// <summary>
	/// 形状装饰器
	/// </summary>
	public abstract class ShapeDecorator : IShape
	{
	protected IShape Shape;

	public ShapeDecorator(IShape shape)
	{
	Shape = shape;
	}

	public virtual void MyShape()
	{
	Shape.MyShape();
	}
	}
	}

	namespace StructuralPattern_DecoratorPattern
	{
	/// <summary>
	/// 红色形状装饰器
	/// </summary>
	public class RedShapeDecorator : ShapeDecorator
	{
	public RedShapeDecorator(IShape shape) : base(shape) { }

	public override void MyShape()
	{
	base.MyShape();
	Console.WriteLine("Turn red\n");
	}
	}
	}

	namespace StructuralPattern_DecoratorPattern
	{
	public class Program
	{
	private static void Main()
	{
	Circle circle = new Circle();
	Square square = new Square();

	RedShapeDecorator redCircle = new RedShapeDecorator(circle);
	RedShapeDecorator redSquare = new RedShapeDecorator(square);

	redCircle.MyShape();
	redSquare.MyShape();
	}
	}
	}

运行结果：
Circle
Turn red

Square
Turn red