CSharp: Command Pattern

 

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/// <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();     }

 

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/// <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);         }     }   }

　　

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/// <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;      }  }

　　

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/// <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;      }  }

　　

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/// <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);         }     } }

　　

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/// <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); }

　　

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/// <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;      }  }

　　

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/// <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：

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/// <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);     }   }

　　

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