【C#设计模式(10)——装饰器模式(Decorator Pattern)】

前言

装饰器模式可以在运行时为对象添加额外的功，而无需修改原始对象的代码。这种方式比继承更加灵活。

代码

//蛋糕类（抽象类）
public abstract class Cake
{
    public  abstract void Create();
}
//奶油蛋糕类
public class CreamCake : Cake
{
    public override void Create()
    {
        Console.WriteLine("制作奶油蛋糕...");
    }
}
//蛋糕装饰器类（抽象类）
public abstract class CakeDecorator : Cake
{
    protected Cake cake;
    protected CakeDecorator(Cake cake)
    {
        this.cake = cake;
    }
    public override void Create()
    {
        cake.Create();
    }
}
//草莓装饰器类
public class StrawberryDecorator : CakeDecorator
{
    public StrawberryDecorator(Cake cake) : base(cake){}
    public override void Create()
    {
        base.Create();
        AddDecorator();
    }
    public void AddDecorator()
    {
        Console.WriteLine("给蛋糕添加草莓..");
    }
}
//芒果装饰器类
public class MangoDecorator : CakeDecorator
{
    public MangoDecorator(Cake cake) : base(cake)
    {
    }

    public override void Create()
    {
        base.Create();
        AddDecorator();
    }
    public void AddDecorator()
    {
        Console.WriteLine("给蛋糕添加芒果..");
    }
}


 /*
  * 结构模型：Structural Pattern
  * 装饰器模式：Decorator Pattern
  */
 internal class Program
 {
     static void Main(string[] args)
     {
         //制作奶油蛋糕
         Cake creamCake = new CreamCake();
         //给奶油蛋糕 + 草莓=>草莓奶油蛋糕
         CakeDecorator strawberryDecorator = new StrawberryDecorator(creamCake);
         //给草莓奶油蛋糕 + 芒果 => 草莓奶油 芒果 蛋糕 
         CakeDecorator mangoDecorator = new MangoDecorator(strawberryDecorator);
         //制作完成
         mangoDecorator.Create();
         Console.ReadLine();
     }
 }

运行结果