乐在其中设计模式(C#) - 组合模式(Composite Pattern)
作者： 介绍 将对象组合成树形结构以表示“部分-整体”的层次结构。它使得客户对单个对象和复合对象的使用具有一致性。 示例 有一个Message实体类，使其单个对象和复合对象具有一致性。 
MessageModel 
using System; using System.Collections.Generic; using System.Text; namespace Pattern.Composite
{ 
/**//// <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.Composite { /**//// <summary> /// 抽象Message实体构件（Component） /// </summary> public abstract class MessageModelComponent { /**//// <summary> /// Message实体对象 /// </summary> protected MessageModel _messageModel; /**//// <summary> /// 名称 /// </summary> protected string _name; /**//// <summary> /// 构造函数 /// </summary> /// <param name="name">名称</param> /// <param name="mm">Message实体对象</param> public MessageModelComponent(string name, MessageModel mm) { this._name = name; this._messageModel = mm; } /**//// <summary> /// 构造函数 /// </summary> /// <param name="name">名称</param> public MessageModelComponent(string name) { this._name = name; } /**//// <summary> /// 添加 /// </summary> /// <param name="mmc">MessageModelComponent</param> public abstract void Add(MessageModelComponent mmc); /**//// <summary> /// 删除 /// </summary> /// <param name="mmc">MessageModelComponent</param> public abstract void Remove(MessageModelComponent mmc); /**//// <summary> /// 获取 /// </summary> /// <param name="indent">缩进数</param> /// <returns></returns> public abstract string GetData(int indent); }} using System; using System.Collections.Generic; using System.Text; namespace Pattern.Composite { /**//// <summary> /// Message实体树叶（Leaf） /// </summary> public class MessageModelLeaf : MessageModelComponent { /**//// <summary> /// 构造函数 /// </summary> /// <param name="name">名称</param> /// <param name="mm">Message实体对象</param> public MessageModelLeaf(string name, MessageModel mm) : base(name, mm) { } /**//// <summary> /// 添加 /// </summary> /// <param name="mmc">MessageModelComponent</param> public override void Add(MessageModelComponent mmc) { throw new Exception("不能添加"); } /**//// <summary> /// 删除 /// </summary> /// <param name="mmc">MessageModelComponent</param> public override void Remove(MessageModelComponent mmc) { throw new Exception("不能删除"); } /**//// <summary> /// 获取 /// </summary> /// <param name="indent">缩进数</param> /// <returns></returns> public override string GetData(int indent) { return new String('—', indent) + "树叶名称：" + _name + "；信息内容：" + _messageModel.Message + "<br />"; } }} using System; using System.Collections.Generic; using System.Text; namespace Pattern.Composite { /**//// <summary> /// Message实体树枝（Composite） /// </summary> public class MessageModelComposite : MessageModelComponent { private List<MessageModelComponent> _list; /**//// <summary> /// 构造函数 /// </summary> /// <param name="name">名称</param> public MessageModelComposite(string name) : base(name) { _list = new List<MessageModelComponent>(); } /**//// <summary> /// 添加 /// </summary> /// <param name="mmc">MessageModelComponent</param> public override void Add(MessageModelComponent mmc) { _list.Add(mmc); } /**//// <summary> /// 删除 /// </summary> /// <param name="mmc">MessageModelComponent</param> public override void Remove(MessageModelComponent mmc) { _list.Remove(mmc); } /**//// <summary> /// 获取 /// </summary> /// <param name="indent">缩进数</param> /// <returns></returns> public override string GetData(int indent) { string s = new String('—', indent) + "树枝名称：" + _name + "<br />"; foreach (MessageModelComponent mmc in _list) { s += mmc.GetData(indent + 2); } 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.Composite; public partial class Composite : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { MessageModelComposite root = new MessageModelComposite("树枝A"); root.Add(new MessageModelLeaf("树叶A", new MessageModel("Message内容A", DateTime.Now))); root.Add(new MessageModelLeaf("树叶B", new MessageModel("Message内容B", DateTime.Now))); MessageModelComposite comp = new MessageModelComposite("树枝B"); comp.Add(new MessageModelLeaf("树叶C", new MessageModel("Message内容C", DateTime.Now))); comp.Add(new MessageModelLeaf("树叶D", new MessageModel("Message内容D", DateTime.Now))); root.Add(comp); root.Add(new MessageModelLeaf("树叶E", new MessageModel("Message内容E", DateTime.Now))); MessageModelLeaf l = new MessageModelLeaf("树叶F", new MessageModel("Message内容F", DateTime.Now)); root.Add(l); root.Remove(l); Response.Write(root.GetData(1)); }}