五.Action Pattern(命令模式)

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Action Pattern.aspx.cs" Inherits="Pattern_Action_Pattern" %>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:TextBox ID="tb_result" runat="server" TextMode="MultiLine" Rows="5"></asp:TextBox>
        <asp:Button ID="bt_submit" runat="server" OnClick="bt_submit_Click"  Text="ActionPattern" />
        <select id="strategy_select" runat="server">
            <option value="A" selected="selected">Begin</option>
            <option value="B">Stop</option>
        </select>
    </div>
    </form>
</body>
</html>

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;

/// <summary>
/// 命名模式
/// 好處:1.把執行動作和命令分開,可以隨意新增動作皆點,然後統一一個命令類去調用.
///      2.很容易的設計一個動作對列,一個一個執行.還很方便的Undo前一個動作產生的效果.
/// 缺點:當一個系統動作較多的時候,比如超過500以上的動作的時候,這種模式就會產生500個動作類,這樣實現起來有點不實際.
///
/// </summary>
public partial class Pattern_Action_Pattern : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void bt_submit_Click(object sender, EventArgs e)
    {
        Doing d = null;
        switch (strategy_select.Items[strategy_select.SelectedIndex].Value.ToString())
        {
            case "A":
                d = new Begin();
                break;
            case "B":
                d = new Stop();
                break;
            default:
                break;
        }
        Command c = new ConcreteCommand(d);
        Invoker i = new Invoker();
        i.SetCommand(c);
        tb_result.Text = i.ExecuteCommand();
    }
}
/// <summary>
/// 定義一個命令抽象類
/// </summary>
public abstract class Command
{
    protected Doing doing;
    public Command(Doing _doing)
    {
        this.doing = _doing;
    }

    public abstract string Execute();
}

/// <summary>
/// 定義一個動作抽象類
/// </summary>
public abstract class Doing
{
    public abstract string DoAction();
}

/// <summary>
/// 具體的動作類
/// </summary>
public class Begin : Doing
{
    public override string DoAction()
    {
        return "Begin Action";
    }
}
public class Stop : Doing
{
    public override string DoAction()
    {
        return "Stop Action";
    }
}

/// <summary>
/// 具體的命令類
/// </summary>
class ConcreteCommand : Command
{
    public ConcreteCommand(Doing doing) : base(doing) { }
    public override string Execute()
    {
        return doing.DoAction();
    }
}

/// <summary>
/// 調用命令.由命令啟動動作執行
/// </summary>
class Invoker
{
    public Command command;
    public void SetCommand(Command _command)
    {
        command = _command;
    }
    public string ExecuteCommand()
    {
        return command.Execute();
    }
}

posted on 2007-03-16 08:28 冷火阅读(213) 评论(0) 编辑收藏举报