using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor
{
/// <summary>
/// Message实体类
/// </summary> public class MessageModel { /// <summary> /// 构造函数 /// </summary> /// <param name="msg">Message内容</param> /// <param name="pt">Message发布时间</param> public MessageModel(string msg, DateTime pt) { this._message = msg; this._publishTime = pt; } private string _message; /// <summary> /// Message内容 /// </summary> public string Message { get { return _message; } set { _message = value; } } private DateTime _publishTime; /// <summary> /// Message发布时间 /// </summary> public DateTime PublishTime { get { return _publishTime; } set { _publishTime = value; } } }
}using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor{ /// <summary> /// 抽象元素（Element） /// </summary> public abstract class AbstractElement { /// <summary> /// 执行抽象访问者的Visit()方法（从而执行抽象元素的方法） /// </summary> /// <param name="abstractVisitor">抽象访问者</param> /// <returns></returns> public abstract string Accept(AbstractVisitor abstractVisitor); }}using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor{ /// <summary> /// 操作Message抽象类（Element） /// </summary> public abstract class Message : AbstractElement { private MessageModel _messageModel; /// <summary> /// 构造函数 /// </summary> /// <param name="mm">Message实体对象</param> public Message(MessageModel mm) { this._messageModel = mm; } /// <summary> /// Message实体对象 /// </summary> public MessageModel MessageModel { get { return _messageModel; } set { _messageModel = value; } } /// <summary> /// 执行抽象访问者的Visit()方法（从而执行抽象元素的方法） /// </summary> /// <param name="abstractVisitor">抽象访问者</param> /// <returns></returns> public override string Accept(AbstractVisitor abstractVisitor) { return abstractVisitor.Visit(this); } /// <summary> /// 获取Message /// </summary> /// <returns></returns> public abstract List<MessageModel> Get(); /// <summary> /// 插入Message /// </summary> /// <returns></returns> public abstract bool Insert(); }}using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor{ /// <summary> /// Sql方式操作Message（ConcreteElement） /// </summary> public class SqlMessage : Message { /// <summary> /// 构造函数 /// </summary> /// <param name="mm">Message实体对象</param> public SqlMessage(MessageModel mm) : base(mm) { } /// <summary> /// 获取Message /// </summary> /// <returns></returns> public override List<MessageModel> Get() { List<MessageModel> l = new List<MessageModel>(); l.Add(new MessageModel("SQL方式获取Message", DateTime.Now)); return l; } /// <summary> /// 插入Message /// </summary> /// <returns></returns> public override bool Insert() { // 代码略 return true; } }}using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor{ /// <summary> /// Xml方式操作Message（ConcreteElement） /// </summary> public class XmlMessage : Message { /// <summary> /// 构造函数 /// </summary> /// <param name="mm">Message实体对象</param> public XmlMessage(MessageModel mm) : base(mm) { } /// <summary> /// 获取Message /// </summary> /// <returns></returns> public override List<MessageModel> Get() { List<MessageModel> l = new List<MessageModel>(); l.Add(new MessageModel("XML方式获取Message", DateTime.Now)); return l; } /// <summary> /// 插入Message /// </summary> /// <returns></returns> public override bool Insert() { // 代码略 return true; } }}using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor{ /// <summary> /// 抽象访问者（Visitor） /// </summary> public abstract class AbstractVisitor { /// <summary> /// 执行抽象元素的方法 /// </summary> /// <param name="abstractElement">抽象元素</param> /// <returns></returns> public abstract string Visit(AbstractElement abstractElement); }}using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor{ /// <summary> /// Insert访问者（ConcreteVisitor） /// </summary> public class InsertVisitor : AbstractVisitor { /// <summary> /// 执行Message的Insert()方法 /// </summary> /// <param name="abstractElement">抽象元素</param> /// <returns></returns> public override string Visit(AbstractElement abstractElement) { Message m = abstractElement as Message; return m.Insert().ToString() + "<br />"; } }}using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor{ /// <summary> /// Get访问者（ConcreteVisitor） /// </summary> public class GetVisitor : AbstractVisitor { /// <summary> /// 执行Message的Get()方法 /// </summary> /// <param name="abstractElement">抽象元素</param> /// <returns></returns> public override string Visit(AbstractElement abstractElement) { Message m = abstractElement as Message; return m.Get()[0].Message + " " + m.Get()[0].PublishTime.ToString() + "<br />"; } }}using System;using System.Collections.Generic;using System.Text;namespace Pattern.Visitor{ /// <summary> /// Message集合（ObjectStructure） /// </summary> public class Messages { private List<Message> _list = new List<Message>(); /// <summary> /// 添加一个Message对象 /// </summary> /// <param name="message">Message对象</param> public void Attach(Message message) { _list.Add(message); } /// <summary> /// 移除一个Message对象 /// </summary> /// <param name="message">Message对象</param> public void Detach(Message message) { _list.Remove(message); } /// <summary> /// 执行集合内所有Message对象的Accept()方法（执行抽象访问者的Visit()方法（从而执行抽象元素的方法）） /// </summary> /// <param name="abstractVisitor">抽象访问者</param> /// <returns></returns> public string Accept(AbstractVisitor abstractVisitor) { string s = ""; foreach (Message m in _list) { s += m.Accept(abstractVisitor); } return s; } }}using System;using System.Data;using System.Configuration;using System.Collections;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using Pattern.Visitor;public partial class Visitor : System.Web.UI.Page{ protected void Page_Load(object sender, EventArgs e) { Pattern.Visitor.Messages m = new Pattern.Visitor.Messages(); m.Attach(new SqlMessage(new MessageModel("插入", DateTime.Now))); m.Attach(new XmlMessage(new MessageModel("插入", DateTime.Now))); Response.Write(m.Accept(new InsertVisitor())); Response.Write(m.Accept(new GetVisitor())); }}乐在其中设计模式(C#) - 访问者模式(Visitor Pattern),布布扣,bubuko.com
乐在其中设计模式(C#) - 访问者模式(Visitor Pattern)
原文：http://www.cnblogs.com/lonelyxmas/p/3590366.html
