乐在其中设计模式(C#) - 状态模式(State Pattern)

using System;

using System.Collections.Generic;

using System.Text;



namespace Pattern.State

{

    /**//// <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.State

{

    /**//// <summary>

    /// 状态模式抽象类

    /// </summary>

    public abstract class AbstractMessageState

    {

        /**//// <summary>

        /// Context类型

        /// </summary>

        protected Message _message;



        /**//// <summary>

        /// Context类型属性

        /// </summary>

        public Message Message

        {

            get { return _message; }

            set { _message = value; }

        }



        /**//// <summary>

        /// 改变状态

        /// </summary>

        public abstract void StateChangeCheck();



        /**//// <summary>

        /// 获取Message

        /// </summary>

        /// <returns></returns>

        public abstract List<MessageModel> Get();



        /**//// <summary>

        /// 插入Message

        /// </summary>

        /// <param name="mm">Message实体对象</param>

        /// <returns></returns>

        public abstract bool Insert(MessageModel mm);

    }

}

using System;

using System.Collections.Generic;

using System.Text;



namespace Pattern.State

{

    /**//// <summary>

    /// Xml方式操作Message

    /// </summary>

    public class XmlMessage : AbstractMessageState

    {

        /**//// <summary>

        /// 构造函数

        /// </summary>

        /// <param name="message">Context类型参数</param>

        public XmlMessage(Message message)

        {

            this._message = message;

        }



        /**//// <summary>

        /// 改变状态

        /// </summary>

        public override void StateChangeCheck()

        {

            // 如果UserId是admin则变换状态为SqlMessage

            if (this._message.UserId == "admin")

            {

                this._message.AbstractMessageState = new SqlMessage(this._message);

            }

        }



        /**//// <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>

        /// <param name="mm">Message实体对象</param>

        /// <returns></returns>

        public override bool Insert(MessageModel mm)

        {

            // 代码略

            return true;

        }

    }

}

using System;

using System.Collections.Generic;

using System.Text;



namespace Pattern.State

{

    /**//// <summary>

    /// Sql方式操作Message

    /// </summary>

    public class SqlMessage : AbstractMessageState

    {

        /**//// <summary>

        /// 构造函数

        /// </summary>

        /// <param name="message">Context类型参数</param>

        public SqlMessage(Message message)

        {

            this._message = message;

        }



        /**//// <summary>

        /// 改变状态

        /// </summary>

        public override void StateChangeCheck()

        {



        }



        /**//// <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>

        /// <param name="mm">Message实体对象</param>

        /// <returns></returns>

        public override bool Insert(MessageModel mm)

        {

            // 代码略

            return true;

        }

    }

}

using System;

using System.Collections.Generic;

using System.Text;



namespace Pattern.State

{

    /**//// <summary>

    /// Context类

    /// </summary>

    public class Message

    {

        /**//// <summary>

        /// 类型为状态模式抽象类的私有变量

        /// </summary>

        private AbstractMessageState _abstractMessageState;



        /**//// <summary>

        /// 类型为状态模式抽象类的属性

        /// </summary>

        public AbstractMessageState AbstractMessageState

        {

            get { return _abstractMessageState; }

            set { _abstractMessageState = value; }

        }       



        /**//// <summary>

        /// UserId私有变量

        /// </summary>

        private string _userId;



        /**//// <summary>

        /// UserId

        /// </summary>

        public string UserId

        {

            get { return _userId; }

            set { _userId = value; }

        }



        /**//// <summary>

        /// 构造函数

        /// </summary>

        /// <param name="userId">UserId</param>

        public Message(string userId)

        {

            this._userId = userId;



            _abstractMessageState = new XmlMessage(this);

        }



        /**//// <summary>

        /// 获取Message

        /// </summary>

        /// <returns></returns>

        public List<MessageModel> Get()

        {

            // 修改状态

            _abstractMessageState.StateChangeCheck();



            return _abstractMessageState.Get();

        }



        /**//// <summary>

        /// 插入Message

        /// </summary>

        /// <param name="mm">Message实体对象</param>

        /// <returns></returns>

        public bool Insert(MessageModel mm)

        {

            // 修改状态

            _abstractMessageState.StateChangeCheck();



            return _abstractMessageState.Insert(mm);

        }

    }

}

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.State;



public partial class State : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        Message m = new Message("admin");

        Response.Write(m.Insert(new MessageModel("插入", DateTime.Now)));

        Response.Write("<br />");

        Response.Write(m.Get()[].PublishTime.ToString());

        Response.Write("<br />");



        m = new Message("user");

        Response.Write(m.Insert(new MessageModel("插入", DateTime.Now)));

        Response.Write("<br />");

        Response.Write(m.Get()[].PublishTime.ToString());

        Response.Write("<br />");

    }

}