组合模式（具体案例）

Company.cs

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

namespace Demo
{
    abstract class Company
    {
        protected string name;

        public Company(string name)
        {
            this.name = name;
        }

        public abstract void Add(Company c);
        public abstract void Remove(Company c);
        public abstract void Display(int depth);
        public abstract void LineOfDuty();
    }
}

ConcreateCompany.cs

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

namespace Demo
{
    class ConcreateCompany:Company
    {
        private List children = new List();

        public ConcreateCompany(string name):base(name)
        {

        }

        public override void Add(Company c)
        {
            children.Add(c);
        }

        public override void Remove(Company c)
        {
            children.Remove(c);
        }

        public override void Display(int depth)
        {
            Console.WriteLine(new String('-', depth) + name);

            foreach(Company component in children)
            {
                component.Display(depth + 2);
            }
        }

        public override void LineOfDuty()
        {
            foreach(Company component in children)
            {
                component.LineOfDuty();
            }
        }
    }
}

HRDepartment.cs

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

namespace Demo
{
    class HRDepartment:Company
    {
        public HRDepartment(string name) : base(name)
        {

        }

        public override void Add(Company c)
        {

        }

        public override void Remove(Company c)
        {

        }

        public override void Display(int depth)
        {
            Console.WriteLine(new String('-', depth) + name);
        }

        public override void LineOfDuty()
        {
            Console.WriteLine("{0}1.员工招聘 2.培训管理", name);
        }
    }
}

FinanceDepartment.cs

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

namespace Demo
{
    class FinanceDepartment:Company
    {
        public FinanceDepartment(string name) : base(name)
        {

        }

        public override void Add(Company c)
        {

        }

        public override void Remove(Company c)
        {

        }

        public override void Display(int depth)
        {
            Console.WriteLine(new String('-', depth) + name);
        }

        public override void LineOfDuty()
        {
            Console.WriteLine("{0}1.公司财务 2.收支管理", name);
        }
    }
}

Program.cs

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

namespace Demo
{
    class Program
    {
        static void Main(string[] args)
        {
            ConcreateCompany root = new ConcreateCompany("柳州总公司");
            root.Add(new FinanceDepartment("总公司财务部"));
            root.Add(new HRDepartment("总公司人力资源部"));

            ConcreateCompany comp = new ConcreateCompany("杭州华东分公司");
            comp.Add(new FinanceDepartment("华东分公司财务部"));
            comp.Add(new HRDepartment("华东分公司人力资源部"));

            ConcreateCompany comp1 = new ConcreateCompany("上海办事处");
            comp1.Add(new FinanceDepartment("上海办事处财务部"));
            comp1.Add(new HRDepartment("上海办事处人力资源部"));

            ConcreateCompany comp2 = new ConcreateCompany("北京办事处");
            comp2.Add(new FinanceDepartment("北京办事处财务部"));
            comp2.Add(new HRDepartment("北京办事处人力资源部"));

            root.Add(comp);
            comp.Add(comp1);
            comp.Add(comp2);

            Console.WriteLine("组织架构:\n");
            root.Display(1);
            Console.WriteLine("职责:\n");
            root.LineOfDuty();

            Console.Read();
        }
    }
}

运行结果：