设计模式——组合模式Composite

逻辑非常清晰，代码非常好写的一种设计模式

定义：讲对象组合成树形结构以表示“部分-整体”的层次结构。组合你是是的用户对单个对象和组合对象的使用具有一致性

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 组合模式
{
    class Program
    {
        abstract class Component
        {
            protected string name;
            public Component(string name)
            {
                this.name = name;
            }
            public abstract void Add(Component c);
            public abstract void Remove(Component c);
            public abstract void Display(int depth);
        }
        class Leaf:Component
        {
            public Leaf(string name) : base(name) { }
            public override void Add(Component c)
            {
                Console.WriteLine("cannot add a leaf");
            }
            public override void Remove(Component c)
            {
                Console.WriteLine("cannot remove from leaf");
            }
            public override void Display(int depth)
            {
                Console.WriteLine(new String('-', depth) + name);
            }
        }
        class Composite:Component
        {
            private List children = new List();
            public Composite(string name) : base(name) { }
            public override void Add(Component c)
            {
                children.Add(c);
            }
            public override void Remove(Component c)
            {
                children.Remove(c);
            }
            public override void Display(int depth)
            {
                Console.WriteLine(new String('-', depth) + name);
                foreach (Component component in children)
                    component.Display(depth + 2);
            }
        }
        static void Main(string[] args)
        {
            Composite root = new Composite("root");
            root.Add(new Leaf("Leaf A"));
            root.Add(new Leaf("Leaf B"));

            Composite comp = new Composite("Composite X");
            comp.Add(new Leaf("Leaf XA"));
            comp.Add(new Leaf("Leaf XB"));
            root.Add(comp);

            Composite comp2 = new Composite("Composite X");
            comp2.Add(new Leaf("Leaf XA"));
            comp2.Add(new Leaf("Leaf XB"));
            comp.Add(comp2);

            root.Add(new Leaf("Leaf C"));
            Leaf leaf = new Leaf("Leaf D");
            root.Add(leaf);
            root.Remove(leaf);
            root.Display(1);
            Console.Read();
        }
    }
}

-root
---Leaf A
---Leaf B
---Composite X
-----Leaf XA
-----Leaf XB
-----Composite X
-------Leaf XA
-------Leaf XB
---Leaf C