CSharp: Command Pattern

 

    /// <summary>
    /// defines Command interface
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public interface Command
    {

        /// <summary>
        /// 
        /// </summary>
        void Execute();
        /// <summary>
        /// 
        /// </summary>
        void Undo();
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        bool isUndo();


    }

 

    /// <summary>
    /// Summary description for ColorCommand.
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public class ColorCommand : Command
    {
        protected Color color;			//line color
        protected PictureBox pbox;		//box to draw in
        protected ArrayList drawList;	//list of lines
        protected int x, y, dx, dy;		//coordinates
        /// <summary>
        /// 
        /// </summary>
        /// <param name="pict"></param>
        public ColorCommand(PictureBox pict)
        {
            pbox = pict;	//copy in picture box
            drawList = new ArrayList();	//create list
        }
        /// <summary>
        /// 
        /// </summary>
        public void Execute()
        {
            //create a new line to draw
            DrawData dl = new DrawData(x, y, dx, dy);
            drawList.Add(dl);	//add it to the list
            x = x + dx;			//increment the positions
            y = y + dy;
            pbox.Refresh();
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public bool isUndo()
        {
            return false;
        }
        /// <summary>
        /// 
        /// </summary>
        public void Undo()
        {
            DrawData dl;
            int index = drawList.Count - 1;
            if (index >= 0)
            {
                dl = (DrawData)drawList[index];
                drawList.RemoveAt(index);
                x = dl.getX();
                y = dl.getY();
            }
            pbox.Refresh();
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="g"></param>
        public void draw(Graphics g)
        {
            Pen rpen = new Pen(color, 1);
            int h = pbox.Height;
            int w = pbox.Width;
            //draw all the lines in the list
            for (int i = 0; i < drawList.Count; i++)
            {
                DrawData dl = (DrawData)drawList[i];
                g.DrawLine(rpen, dl.getX(), dl.getY(), dl.getX() + dx, dl.getDy() + h);
            }
        }

    }

　　

   /// <summary>
    /// Summary description for DrawData.
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public class DrawData
    {

        /// <summary>
        /// 
        /// </summary>
        private int x, y, dx, dy;

        /// <summary>
        /// 
        /// </summary>
        /// <param name="x_"></param>
        /// <param name="y_"></param>
        /// <param name="dx_"></param>
        /// <param name="dy_"></param>
        public DrawData(int x_, int y_, int dx_, int dy_)
        {
            x = x_;
            dx = dx_;
            y = y_;
            dy = dy_;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public int getX()
        {
            return x;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public int getY()
        {
            return y;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public int getDx()
        {
            return dx;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public int getDy()
        {
            return dy;
        }
    }

　　

   /// <summary>
    /// Summary description for RedCommand.
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public class RedCommand : ColorCommand
    {

        /// <summary>
        /// 
        /// </summary>
        /// <param name="pict"></param>
        public RedCommand(PictureBox pict)
            : base(pict)
        {
            color = Color.Red;
            x = 0;
            dx = 20;
            y = 0;
            dy = 0;
        }
    }

　　

    /// <summary>
    /// Summary description for UndoCommand.
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public class UndoComd : Command
    {

        /// <summary>
        /// 
        /// </summary>
        private ArrayList undoList;
        /// <summary>
        /// 
        /// </summary>
        public UndoComd()
        {
            undoList = new ArrayList();
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="comd"></param>
        public void add(Command comd)
        {
            if (!comd.isUndo())
            {
                undoList.Add(comd);
            }
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public bool isUndo()
        {
            return true;
        }
        /// <summary>
        /// 
        /// </summary>
        public void Undo() { }
        /// <summary>
        /// 
        /// </summary>
        public void Execute()
        {
            int index = undoList.Count - 1;
            if (index >= 0)
            {
                Command cmd = (Command)undoList[index];
                cmd.Undo();
                undoList.RemoveAt(index);
            }
        }
    }

　　

    /// <summary>
    /// Summary description for CommandHolder.
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public interface CommandHolder
    {

        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        Command getCommand();
        /// <summary>
        /// 
        /// </summary>
        /// <param name="cmd"></param>
        void setCommand(Command cmd);
    }

　　

   /// <summary>
    /// draws bluelines and caches list for undo
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public class BlueCommand : ColorCommand
    {

        /// <summary>
        /// 
        /// </summary>
        /// <param name="pict"></param>
        public BlueCommand(PictureBox pict)
            : base(pict)
        {
            color = Color.Blue;
            x = pbox.Width;
            dx = -20;
            y = 0;
            dy = 0;
        }
    }

　　

   /// <summary>
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public partial class CommandButton : Button, CommandHolder
    {

        private Command command;
        /// <summary>
        /// 
        /// </summary>
        /// <param name="comd"></param>
        public void setCommand(Command comd)
        {
            command = comd;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public Command getCommand()
        {
            return command;
        }


        public CommandButton()
        {
            InitializeComponent();
        }

        public CommandButton(IContainer container)
        {
            container.Add(this);

            InitializeComponent();
        }
    }

　　

调用试试：

    /// <summary>
    /// Command Patterns
    /// Command Patterns命令模式
    /// 20220918
    /// geovindu,Geovin Du,涂聚文
    /// </summary>
    public partial class CommandPatternsForm : Form
    {
        private BlueCommand blueC;
        private RedCommand redC;
        private UndoComd undoC;

        /// <summary>
        /// 
        /// </summary>
        public CommandPatternsForm()
        {
            InitializeComponent();
            init();
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void CommandPatternsForm_Load(object sender, EventArgs e)
        {

        }


        /// <summary>
        /// 
        /// </summary>
        private void init()
        {
            btBlue.setCommand(blueC = new BlueCommand(pBox));
            btRed.setCommand(redC = new RedCommand(pBox));
            btUndo.setCommand(undoC = new UndoComd());

            EventHandler evh = new EventHandler(commandClick);
            btBlue.Click += evh;
            btRed.Click += evh;
            btUndo.Click += evh;
            pBox.Paint += new PaintEventHandler(paintHandler);

        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void commandClick(object sender, EventArgs e)
        {
            //get the command
            Command comd = ((CommandHolder)sender).getCommand();
            undoC.add(comd);	//add to undo list
            comd.Execute();	//and execute it
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        public void paintHandler(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            blueC.draw(g);
            redC.draw(g);
        }

    }

　　

输出：