C# 组合模式（Component）

理解：整体与部分的层次关系，且树形关系中的所有对象都有相同的操作

代码：

using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace DesignMode.Component
{
    //职位
    public abstract class Position
    {
        protected string _name;
        public Position(string name)
        {
            _name = name;
        }

        public abstract void AddUnderPosition(Position post);
        public abstract void RemoveUnderPosition(Position post);
        public abstract string DisplayUnderPosition(int depth);
    }

    //管理职位
    public class Manager : Position
    {
        private IList<Position> subs = new List<Position>();

        public Manager(string name)
            : base(name)
        { }

        public override void AddUnderPosition(Position post)
        {
            subs.Add(post);
        }

        public override void RemoveUnderPosition(Position post)
        {
            subs.Remove(post);
        }

        public override string DisplayUnderPosition(int depth)
        {
            string dis = "";
            dis += new String('-', depth) + _name + "\n";
            foreach (Position p in subs)
            {
               dis += p.DisplayUnderPosition(depth + 2);
            }
            return dis;
        }
    }

    //普通职员
    public class Employee : Position
    {
        public Employee(string name)
            : base(name)
        { }

        public override void AddUnderPosition(Position post)
        {
            MessageBox.Show("不能添加下属职位");
        }

        public override void RemoveUnderPosition(Position post)
        {
            MessageBox.Show("不能移除下属职位");
        }

        public override string DisplayUnderPosition(int depth)
        {
            string dis = "";
            dis += new String('-', depth) + _name + "\n";
            return dis;
        }
    }

}

 客户端代码：

        private void btn_Component_Click(object sender, EventArgs e)
        {
            Manager chairman = new Manager("懂事长");
            chairman.AddUnderPosition(new Employee("秘书"));
            chairman.AddUnderPosition(new Employee("助理"));

            Manager buss = new Manager("业务经理");
            buss.AddUnderPosition(new Employee("销售员"));

            Manager tech = new Manager("技术经理");
            tech.AddUnderPosition(new Employee("程序员"));

            chairman.AddUnderPosition(buss);
            chairman.AddUnderPosition(tech);

            string display = chairman.DisplayUnderPosition(1);
            MessageBox.Show(display);  }