乐在其中设计模式(C#) - 工厂方法模式(Factory .doc

介绍定义一个用于创建对象的接口，让子类决定将哪一个类实例化。Factory Method使一个类的实例化延迟到其子类。示例有SqlMessage和XmlMessage，用Factory Method来实例化它们。MessageModelusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.FactoryMethod/*/Message实体类/publicclassMessageModel/*/构造函数/Message内容/Message发布时间publicMessageModel(stringmsg,DateTimept)this._message=msg;this._publishTime=pt; privatestring_message;/*/Message内容/publicstringMessagegetreturn_message;set_message=value;privateDateTime_publishTime;/*/Message发布时间/publicDateTimePublishTimegetreturn_publishTime;set_publishTime=value;AbstractMessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.FactoryMethod/*/操作Message抽象类（Product）/publicabstractclassAbstractMessage/*/获取Message/publicabstractListGet();/*/插入Message/Message实体对象/publicabstractboolInsert(MessageModelmm);SqlMessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text; namespacePattern.FactoryMethod/*/Sql方式操作Message（ConcreteProduct）/publicclassSqlMessage:AbstractMessage/*/获取Message/publicoverrideListGet()Listl=newList();l.Add(newMessageModel(SQL方式获取Message,DateTime.Now);returnl;/*/插入Message/Message实体对象/publicoverrideboolInsert(MessageModelmm)/代码略returntrue;XmlMessageusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.FactoryMethod/*/Xml方式操作Message（ConcreteProduct）/publicclassXmlMessage:AbstractMessage/*/获取Message/publicoverrideListGet()Listl=newList();l.Add(newMessageModel(XML方式获取Message,DateTime.Now);returnl;/*/插入Message/Message实体对象/publicoverrideboolInsert(MessageModelmm)/代码略returntrue;AbstractMessageFactoryusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.FactoryMethod/*/抽象Message工厂（Creator）/publicabstractclassAbstractMessageFactory/AnOperation/*/工厂方法/AbstractMessagepublicabstractAbstractMessageCreateMessage();SqlMessageFactoryusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.FactoryMethod/*/SqlMessage工厂（ConcreteCreator）/publicclassSqlMessageFactory:AbstractMessageFactory/*/实现工厂方法，返回SqlMessage对象/publicoverrideAbstractMessageCreateMessage()returnnewSqlMessage();XmlMessageFactoryusingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespacePattern.FactoryMethod/*/XmlMessage工厂（ConcreteCreator）/publicclassXmlMessageFactory:AbstractMessageFactory/*/实现工厂方法，返回XmlMessage对象/publicoverrideAbstractMessageCreateMessage()returnnewXmlMessage();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.FactoryMethod;publicpartialclassFactoryMethod:System.Web.UI.PageprotectedvoidPage_Load(objectsender,EventArgse)AbstractMessageFactoryamf=newSqlMessageFactory();AbstractMessageam=amf.CreateMessage();Response.Write(am.Insert(newMessageModel(插入,DateTime.Now);Response.Write();Response.Write(am.Get()0.Message+am.Get()0.PublishTime.ToString();Response.Write();amf=newXmlMessageFactory();am=amf.CreateMessage();Response.Write(am.Insert(newMessageModel(插入,DateTime