命令模式

/*
 * User: Administrator
 * Date: 2007-7-2 Time: 15:49
  */
// 一些命令,作用是画圆,画方,画线,三个主要的命令,
// 命令模式最主的特点是,可以方便的加入权限的判断
// 最后便使用了一个代理模式,来实现这个权限的判断
//
using  System;
using  System.Drawing;
using  System.Windows.Forms;
namespace  SecurityCommand{

     public   abstract   class  Command{
         private  Graphics g;
         public  Command(){}
         public  Graphics cav{
             get { return  g;}
             set {g = value;}
        }

         public   abstract   void  Execute();
    }

     public   class  CircleCommand:Command{
         public  CircleCommand(){}

         public   override   void  Execute()
        {
            Pen p = new  Pen(Color.Red);
             this .cav.DrawEllipse(p, 0 , 0 , 100 , 100 );
        }
    }

     public   class  LineCommand:Command{
         public  LineCommand(){}
         public   override   void  Execute()
        {
            Pen p = new  Pen(Color.Red);
             this .cav.DrawLine(p, 0 , 0 , 100 , 100 );
        }
    }

     public   class  RectCommand:Command{
         public  RectCommand(){}

         public   override   void  Execute()
        {
            Pen p = new  Pen(Color.Red);
             this .cav.DrawRectangle(p, 0 , 0 , 100 , 100 );
        }
    }


     public   class  SecurityCommand:Command{
         private  Command c;

         public  SecurityCommand(Command c){
             this .c = c;
        }

         public   override   void  Execute()
        {
            MessageBox.Show( " 权限判断 " + c.GetType().Name);
            c.Execute();
        }
    }
}


// 界面的函数
//
/*
 * User: Administrator
 * Date: 2007-7-2 Time: 15:51
  */

using  System;
using  System.Drawing;
using  System.Windows.Forms;
using  SecurityCommand;

namespace  myMemonto
{
     ///   <summary>
     ///  Description of MyDraw.
     ///   </summary>
     public   partial   class  MyDraw : Form
    {
         private  Command circle;
         private  Command line;
         private  Command rect;

         private  Command scircle;
         private  Command sline;
         private  Command sRect;

        [STAThread]
         public   static    void  Main(){
            Application.Run( new  MyDraw());
        }

         public  MyDraw()
        {
             //
             //  The InitializeComponent() call is required for Windows Forms designer support.
             //
            InitializeComponent();
            Init();
            scircle = new  SecurityCommand.SecurityCommand(circle);
            sline = new  SecurityCommand.SecurityCommand(line);
            sRect = new  SecurityCommand.SecurityCommand(rect);

             //
             //  TODO: Add constructor code after the InitializeComponent() call.
             //
        }

         void  Init(){
            circle = new  SecurityCommand.CircleCommand();
            circle.cav = this .CreateGraphics();

            line = new  SecurityCommand.LineCommand();
            line.cav = this .CreateGraphics();

            rect = new  SecurityCommand.RectCommand();
            rect.cav = this .CreateGraphics();
        }

         void  TsmCircleClick( object  sender, EventArgs e)
        {
            scircle.Execute();
        }

         void  TsmLineClick( object  sender, EventArgs e)
        {
            sline.Execute();
        }

         void  TsmRectClick( object  sender, EventArgs e)
        {
            sRect.Execute();
        }

         void  TsmExitClick( object  sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}