乐在其中设计模式

介绍保证一个类仅有一个实例，并提供一个访问它的全局访问点。示例保证一个类仅有一个实例。Single1011^^tenericClass-属性雪Instance:T-■套类型ISingletonCreatar[AClass-字段二，inst：±tlch:T泛型实现单例模式SingletonusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Singleton日田{白中///<summary>I///泛型实现单例模式///</summary>卜///<typeparamname="T">需要实现单例的类</typeparam>publicclassSingleton<T>whereT:new()摊{斡///<summary>I///返回类的实例///</summary>publicstaticTInstance白中{H申get{returnSingletonCreator.instance;}}IclassSingletonCreator摊{internalstaticreadonlyTinstance=newT();b}TestusingSystem;usingSystem.Data;usingSystem.Configuration;usingSystem.Collections;usingSystem.Web;usingSystem.Web.Security;usingSystem.Web.UI;usingSystem.Web.UI.WebControls;usingSystem.Web.UI.WebControls.WebParts;usingSystem.Web.UI.HtmlControls;usingPattern.Singleton;publicpartialclassSingleton:System.Web.UI.Page曰田{protectedvoidPage_Load(objectsender,EventArgse)白中{//使用单例模式，保证一个类仅有一个实例Response.Write(Singleton<Test>.Instance.Time);Response.Write("<br/>");IResponse.Write(Singleton<Test>.Instance.Time);Response.Write("<br/>");I//不用单例模式I Testt=newTest();I Response.Write(t.Time);Response.Write("<br/>");I Testt2=newTest();I Response.Write(t2.Time);Response.Write("<br/>");}}publicclassTest曰田{privateDateTime_time;IIpublicTest()白中{ISystem.Threading.Thread.Sleep(3000);_time=DateTime.Now;}publicstringTime由由{get{return_time.ToString();}}}运行结果2007-2-1022:35:112007-2-1022:35:112007-2-1022:35:142007-2-1022:35:17乐在其中设计模式(C#)-适配器模式(AdapterPattern)介绍将一个类的接口转换成客户希望的另外一个接口。Adapter模式使得原本由于接口不兼容而不能一起工作的那些类可以一起工作。示例有一个Message实体类，某个类对它的操作有Insert()和Get()方法。现在需要把这个类转到另一个接口，分别对应Add()和Select()方法。

MessageModelusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Adapter曰田｛摊///<summary>I///Message实体类///</summary>publicclassMessageModel摊{斡///<summary>I ///构造函数///</summary>I ///<paramname="msg">Message内容</param>///<paramname="pt">Message发布时间</param>publicMessageModel(stringmsg,DateTimept)白中{this._message=msg;this._publishTime=pt;}privatestring_message;白中///<summary>///Message内容///</summary>publicstringMessage白中{get{return_message;}set{_message=value;}}privateDateTime_publishTime;白中///<summary>I ///Message发布时间///</summary>publicDateTimePublishTime白中{get{return_publishTime;}set{_publishTime=value;}}}}SqlMessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Adapter曰田{摊///<summary>I///源(Adaptee)角色I///Sql方式操作Message///</summary>publicclassSqlMessage白中{R申///<summary>I///获取Message///</summary>///<returns></returns>publicList<MessageModel>Get()白中{List<MessageModel>l=newList<MessageModel>();l.Add(newMessageModel("SQL方式获取Message",DateTime.Now));IIreturnl;}摊///<summary>///插入Message///</summary>I///<paramname="mm">Message实体对象</param>///<returns></returns>publicboolInsert(MessageModelmm)摊{〃代码略Ireturntrue;}}}IMessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Adapter日田{白中///<summary>I///目标(Target)角色I///操作Message的接口卜///</summary>IpublicinterfaceIMessage{斡///<summary>I ///获取Message///</summary>卜 ///<returns></returns>I List<MessageModel>Select();I白中///<summary>I /// 插入MessageI /// </summary>I /// <paramname="mm">Message实体对象</param>卜 /// <returns></returns>I boolAdd(MessageModelmm);}}MessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Adapter曰田{摊///<summary>I///适配器(Adapter)角色I ///类适配器I ///把源适配到这个类///</summary>publicclassMessage:SqlMessage,IMessage摊{斡///<summary>I///获取Message///</summary>///<returns></returns>publicList<MessageModel>Select()百中{returnbase.Get();}摊///<summary>///插入Message///</summary>I///<paramname="mm">Message实体对象</param>///<returns></returns>publicboolAdd(MessageModelmm)摊{returnbase.Insert(mm);}}}Message?usingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.Adapter曰田{摊///<summary>I///适配器(Adapter)角色I///对象适配器I///把源适配到这个类///</summary>publicclassMessage?:IMessage摊{privateSqlMessage_sqlMessage;白中///<summary>I///构造函数///</summary>publicMessage2()白中{_sqlMessage=newSqlMessage();}白中///<summary>I///获取Message///</summary>///<returns></returns>publicList<MessageModel>Select()百中{return_sqlMessage.Get();}摊///<summary>///插入Message///</summary>I///<paramname="mm">Message实体对象</param>///<returns></returns>publicboolAdd(MessageModelmm)摊{return_sqlMessage.Insert(mm);}}}clientusingSystem;usingSystem.Data;usingSystem.Configuration;usingSystem.Collections;usingSystem.Web;usingSystem.Web.Security;usingSystem.Web.UI;usingSystem.Web.UI.WebControls;usingSystem.Web.UI.WebControls.WebParts;usingSystem.Web.UI.HtmlControls;usingPattern.Adapter;publicpartialclassAdapter:System.Web.UI.Page曰田{protectedvoidPage_Load(objectsender,EventArgse)白中{IMessagem;I m=newMessage();I Response.Write("类适配器方式<br/>");I Response.Write(m.Add(newMessageModel("插入"，DateTime.Now)));Response.Write("<br/>");I Response.Write(m.Select()[0].Message + " " + m.Select()[0].PublishTime.ToString());Response.Write("<br/><br/>");II m=newMessage2();I Response.Write("对象适配器方式<br/>");I Respo