原文:
乐在其中设计模式(C#) - 策略模式(Strategy Pattern)
作者： webabcd
介绍
定义一系列的算法，把它们一个个封装起来，并且使它们可相互替换。本模式使得算法的变化可独立于使用它的客户。
示例
有一个Message实体类，对它的操作有Insert()和Get()方法，持久化数据在SqlServer数据库中或Xml文件里（两种可互换的算法）。由客户端决定使用哪种算法。
MessageModel
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{
/// <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; }
}
}
}
IMessageStrategy
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{
/// <summary>
/// 策略接口
/// </summary>
public interface IMessageStrategy
{
/// <summary>
/// 获取Message
/// </summary>
/// <returns></returns>
List<MessageModel> Get();
/// <summary>
/// 插入Message
/// </summary>
/// <param name="mm">Message实体对象</param>
/// <returns></returns>
bool Insert(MessageModel mm);
}
}
SqlMessage
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{
/// <summary>
/// Sql方式操作Message
/// </summary>
public class SqlMessage : IMessageStrategy
{
/// <summary>
/// 获取Message
/// </summary>
/// <returns></returns>
public 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>
/// <param name="mm">Message实体对象</param>
/// <returns></returns>
public bool Insert(MessageModel mm)
{
// 代码略
return true;
}
}
}
XmlMessage
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{
/// <summary>
/// Xml方式操作Message
/// </summary>
public class XmlMessage : IMessageStrategy
{
/// <summary>
/// 获取Message
/// </summary>
/// <returns></returns>
public 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>
/// <param name="mm">Message实体对象</param>
/// <returns></returns>
public bool Insert(MessageModel mm)
{
// 代码略
return true;
}
}
}
Message
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{
/// <summary>
/// Context类
/// </summary>
public class Message
{
/// <summary>
/// 声明一个IMessageStrategy类型
/// </summary>
private IMessageStrategy _strategy;
/// <summary>
/// 构造函数
/// </summary>
/// <param name="strategy">具体算法</param>
public Message(IMessageStrategy strategy)
{
this._strategy = strategy;
}
/// <summary>
/// 获取Message
/// </summary>
/// <returns></returns>
public List<MessageModel> Get()
{
return _strategy.Get();
}
/// <summary>
/// 插入Message
/// </summary>
/// <param name="mm">Message实体对象</param>
/// <returns></returns>
public bool Insert(MessageModel mm)
{
return _strategy.Insert(mm);
}
}
}
client
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.Strategy;
public
partial
class
Strategy : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Message m = new Message(new XmlMessage());
Response.Write(m.Insert(new MessageModel("插入", DateTime.Now)));
Response.Write("<br />");
Response.Write(m.Get()[0].Message + " " + m.Get()[0].PublishTime.ToString());
Response.Write("<br />");
m = new Message(new SqlMessage());
Response.Write(m.Insert(new MessageModel("插入", DateTime.Now)));
Response.Write("<br />");
Response.Write(m.Get()[0].Message + " " + m.Get()[0].PublishTime.ToString());
Response.Write("<br />");
}
}
运行结果
True
XML方式获取Message 2007-2-10 22:42:44
True
SQL方式获取Message 2007-2-10 22:42:44
参考
http://www.dofactory.com/Patterns/PatternStrategy.aspx
OK
[源码下载]
乐在其中设计模式(C#) - 策略模式(Strategy Pattern)
作者： webabcd
介绍
定义一系列的算法，把它们一个个封装起来，并且使它们可相互替换。本模式使得算法的变化可独立于使用它的客户。
示例
有一个Message实体类，对它的操作有Insert()和Get()方法，持久化数据在SqlServer数据库中或Xml文件里（两种可互换的算法）。由客户端决定使用哪种算法。
MessageModel
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{
/// <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; } } }}
IMessageStrategy
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{ /// <summary> /// 策略接口 /// </summary> public interface IMessageStrategy { /// <summary> /// 获取Message /// </summary> /// <returns></returns> List<MessageModel> Get(); /// <summary> /// 插入Message /// </summary> /// <param name="mm">Message实体对象</param> /// <returns></returns> bool Insert(MessageModel mm); }}
SqlMessage
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{ /// <summary> /// Sql方式操作Message /// </summary> public class SqlMessage : IMessageStrategy { /// <summary> /// 获取Message /// </summary> /// <returns></returns> public 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> /// <param name="mm">Message实体对象</param> /// <returns></returns> public bool Insert(MessageModel mm) { // 代码略 return true; } }}
XmlMessage
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{ /// <summary> /// Xml方式操作Message /// </summary> public class XmlMessage : IMessageStrategy { /// <summary> /// 获取Message /// </summary> /// <returns></returns> public 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> /// <param name="mm">Message实体对象</param> /// <returns></returns> public bool Insert(MessageModel mm) { // 代码略 return true; } }}
Message
using
System;
using
System.Collections.Generic;
using
System.Text;
namespace
Pattern.Strategy
{ /// <summary> /// Context类 /// </summary> public class Message { /// <summary> /// 声明一个IMessageStrategy类型 /// </summary> private IMessageStrategy _strategy; /// <summary> /// 构造函数 /// </summary> /// <param name="strategy">具体算法</param> public Message(IMessageStrategy strategy) { this._strategy = strategy; } /// <summary> /// 获取Message /// </summary> /// <returns></returns> public List<MessageModel> Get() { return _strategy.Get(); } /// <summary> /// 插入Message /// </summary> /// <param name="mm">Message实体对象</param> /// <returns></returns> public bool Insert(MessageModel mm) { return _strategy.Insert(mm); } }}
client
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.Strategy;
public
partial
class
Strategy : System.Web.UI.Page
{ protected void Page_Load(object sender, EventArgs e) { Message m = new Message(new XmlMessage()); Response.Write(m.Insert(new MessageModel("插入", DateTime.Now))); Response.Write("<br />"); Response.Write(m.Get()[0].Message + " " + m.Get()[0].PublishTime.ToString()); Response.Write("<br />"); m = new Message(new SqlMessage()); Response.Write(m.Insert(new MessageModel("插入", DateTime.Now))); Response.Write("<br />"); Response.Write(m.Get()[0].Message + " " + m.Get()[0].PublishTime.ToString()); Response.Write("<br />"); }}
运行结果
True
XML方式获取Message 2007-2-10 22:42:44
True
SQL方式获取Message 2007-2-10 22:42:44
参考
http://www.dofactory.com/Patterns/PatternStrategy.aspx
OK
[源码下载]
