模式角色与结构：

示例代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace CSharp.DesignPattern.VisitorPattern{    class Program    {        static void Main(string[] args)        {            ObjectStructure list = new ObjectStructure();            list.AddEmployee(new FulltimeEmployee("Mike", 2000));            list.AddEmployee(new FulltimeEmployee("Tony", 3000));            list.AddEmployee(new ParttimeEmployee("Nancen", 800));            list.AddEmployee(new ParttimeEmployee("Bibo", 500));            FinanceVisitor fVisitor = new FinanceVisitor();            HrVisitor hVisitor = new HrVisitor();            list.Accept(fVisitor);            list.Accept(hVisitor);        }    }    class ObjectStructure    {        public void Accept(Visitor visitor)        {            foreach (IEmployee element in employees)            {                element.Accept(visitor);            }        }        public void AddEmployee(IEmployee employee)        {            employees.Add(employee);        }        public void RemoveEmployee(IEmployee employee)        {            employees.Remove(employee);        }        private List
     
       employees = new List
      
       ();    }    class Visitor    {        public abstract void Visit(FulltimeEmployee fulltime);        public abstract void Visit(ParttimeEmployee contract);    }    class FinanceVisitor : Visitor    {        public void Visit(FulltimeEmployee fulltime)        {            Console.Write("The wage of fulltime is ...");         }        public void Visit(ParttimeEmployee contract)        {            Console.Write("The wage of parttime is ...");         }    }    class HrVisitor : Visitor    {        public void Visit(FulltimeEmployee fulltime)        {            Console.Write("The worktime of fulltime is ...");            Console.Write("The overtime of fulltime is ...");            Console.Write("The timeoff of fulltime is ...");         }        public void Visit(ParttimeEmployee contract)        {            Console.Write("The worktime of fulltime is ...");         }    }    interface IEmployee    {        public void Accept(Visitor visitor)        { }        String Name { set; get; }        Int32 Wage { set; get; }    }    class FulltimeEmployee : IEmployee    {        public FulltimeEmployee(String name, Int32 wage)        {            this._name = name;            this._wage = wage;        }        public void Accept(Visitor visitor)        {            visitor.Visit(this);        }        public void OperationFulltime()        { }        public string Name        {            get { return _name; }            set { _name = value; }        }        public int Wage        {            get { return _wage; }            set { _wage = value; }        }        private String _name;        private Int32 _wage;    }    class ParttimeEmployee : IEmployee    {        public ParttimeEmployee(String name, Int32 wage)        {            this._name = name;            this._wage = wage;        }        public void Accept(Visitor visitor)        {            visitor.Visit(this);        }        public void OperationParttime()        { }        public string Name        {            get { return _name; }            set { _name = value; }        }        public int Wage        {            get { return _wage; }            set { _wage = value; }        }        private String _name;        private Int32 _wage;    }}