大话设计-装饰模式

装饰模式的核心：被装饰对象（最原始），装饰对象（带有装饰功能的被装饰对象）。

假设有一个被装饰对象叫“concretecomponent ”，两个装饰对象叫“concretedecoratora”、“concretedecoratorb”。装饰是锦上添花的事情，concretecomponent 被装饰之前已经最好了最基本的工作，concretedecoratora和concretedecoratorb只是在这个基本工作里额外加了些工作。

装饰是无序的，可以concretedecoratora先装饰concretecomponent，然后concretedecoratorb装饰concretedecoratora。也可以concretedecoratorb先装饰concretecomponent，然后concretedecoratora装饰concretedecoratorb。

被装饰对象和装饰类是否需要抽象跟这里的装饰模式无关。

using system;

namespace consoleapp4
{
    class program
    {
        public static void main(string[] args)
        {
            concretecomponent concretecomponent = new concretecomponent();
            concretedecoratora concretedecoratora = new concretedecoratora();
            concretedecoratorb concretedecoratorb = new concretedecoratorb();

            concretedecoratora.setcomponent(concretecomponent);
            concretedecoratorb.setcomponent(concretedecoratora);
            concretedecoratorb.operation();
        }
    }
    
    abstract class component
    {
        public abstract void operation();
    }

    class concretecomponent:component
    {
        public override void operation()
        {
            console.writeline("具体对象的操作");
        }
    }

     abstract class decorator : component
    {
        protected component component;
        public void setcomponent(component component)
        {
            this.component = component;
        }
        public override void operation()
        {
            if (component != null)
            {
                component.operation();
            }
        }
    }

     class concretedecoratora : decorator
    {
        private string addstate;
        public override void operation()
        {
            base.operation();
            addstate = "a addstate";
            console.writeline("a类装饰");
        }
    }

    class concretedecoratorb : decorator
    {
        private string addstate;
        public override void operation()
        {
            base.operation();
            addstate = "b addstate";
            console.writeline("b类装饰");
        }
    }
}

using system;

namespace consoleapp4
{
    class program
    {
        public static void main(string[] args)
        {            
            person person = new person("白石");
            tshirts shirts = new tshirts();
            overalls overalls = new overalls();

            shirts.decorate(person);
            overalls.decorate(shirts);
        }
    }
    
   class person
    {
        public person()
        {

        }
        private string name;
        public person (string name)
        {
            this.name = name;
        }
        public virtual void show()
        {
            // 什么装饰都没有的基本展示。
            console.writeline($"{name} 一个人的基本show");
        }
    }

    abstract class finery : person
    {
        protected person component;
        public void decorate(person person)
        {
            this.component = person;
        }
        public override void show()
        {
            if (component != null)
            {
                component.show();
            }
        }
    }

    class tshirts : finery
    {
        public override void show()
        {
            base.show();
            console.writeline("穿t恤");
        }
    }

    class overalls : finery
    {
        public override void show()
        {
            base.show();
            console.writeline("工装裤");
        }
    }
}