snake v0.5

 为了学习.net，学着写了这个小游戏。顺便实践一下OO了。请高手指教。

// form1.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Timers;

namespace snake
...{
    public partial class GameBox : Form
    ...{
        private System.Timers.Timer timer;
        private GameBoxStatus status;
        private Snake snake;

        public GameBox()
        ...{
            InitializeComponent();
            status = GameBoxStatus.OFF;
        }

        public void Turn(Direction direction)
        ...{
            if (status == GameBoxStatus.ON)
            ...{
                snake.Turn(direction);
            }   
        }

        public void Power()
        ...{
            if (status == GameBoxStatus.ON)
            ...{
                PowerOff();
            }
            else
            ...{
                PowerOn();
            }
        }

        private void PowerOn()
        ...{
            // 初始化timer
            timer = new System.Timers.Timer();
            timer.AutoReset = true;
            timer.Enabled = false;
            timer.Interval = 100;
            
            // 初始化snake
            snake = new Snake(drawingPanel, timer);


            timer.Elapsed += new ElapsedEventHandler(snake.Move);

            status = GameBoxStatus.ON;
        }

        private void PowerOff()
        ...{
            //snake.EraseAllBlocks();
            // 通知绘图区清空
            Graphics graphics = drawingPanel.CreateGraphics();
            graphics.Clear(Color.White);

            // 销毁当前的snake对象
            snake.DestroySnake();
            snake = null;

            timer.Stop();
            timer = null;

            status = GameBoxStatus.OFF;
        }


        //
        private void powerButton_Click(object sender, EventArgs e)
        ...{
            Power();
        }

        private void upButton_Click(object sender, EventArgs e)
        ...{
            Turn(Direction.UP);
        }

        private void leftButton_Click(object sender, EventArgs e)
        ...{
            Turn(Direction.LEFT);
        }

        private void downButton_Click(object sender, EventArgs e)
        ...{
            Turn(Direction.DOWN);
        }

        private void rightButton_Click(object sender, EventArgs e)
        ...{
            Turn(Direction.RIGHT);
        }

        private void pauseButton_Click(object sender, EventArgs e)
        ...{
            if (status == GameBoxStatus.ON)
            ...{
                snake.Pause();
            }
        }

        private void continueButton_Click(object sender, EventArgs e)
        ...{
            if (status == GameBoxStatus.ON)
            ...{
                snake.Resume();
            }
        }   
    }

    enum GameBoxStatus
    ...{
        ON, OFF
    }

    public enum Direction
    ...{
        UP, DOWN, LEFT, RIGHT
    }
}

// snake.cs
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Drawing;

namespace snake
...{
    class Snake
    ...{
        private Graphics graphics;
        private System.Timers.Timer timer;

        private SnakeStatus status;
        private Direction direction;

        //private SnakeBody snakeBody;

        private bool isDirectionChangeAllowed;


        与块有关***************************************************************************#region 与块有关***************************************************************************

        protected Block headBlock = null;
        protected Block tailBlock = null;
        protected int BlockCount = 0;

        public Block HeadBlock
        ...{
            get
            ...{
                return headBlock;
            }
        }

        public Block TailBlock
        ...{
            get
            ...{
                return tailBlock;
            }
        }

        // 在蛇尾部追加一个块
        public void AppendBlock(Block block)
        ...{
            if (IsBlockListEmpty())
            ...{
                headBlock = block;
                tailBlock = block;
            }
            else
            ...{
                tailBlock.Next = block;
                block.Previous = tailBlock;
                tailBlock = block;
                tailBlock.Next = headBlock;
                headBlock.Previous = tailBlock;
            }
            BlockCount++;
        }

        public void DrawAllBlocks()
        ...{
            Block current = headBlock;
            for (int i = 0; i < BlockCount; i++)
            ...{
                current.Draw(graphics);
                current = current.Next;
            }
        }

        public void DestroySnake()
        ...{
            BlockCount = 0;
            headBlock = null;
            tailBlock = null;
        }

        public void EraseAllBlocks()
        ...{
            Block current = headBlock;
            for (int i = 0; i < BlockCount; i++)
            ...{
                current.Erase(graphics);
                current = current.Next;
            }
        }

        protected void Rotate()
        ...{
            tailBlock = tailBlock.Previous;
            headBlock = headBlock.Previous;
        }

        // 是否为空
        private bool IsBlockListEmpty()
        ...{
            if (BlockCount == 0)
            ...{
                return true;
            }
            return false;
        }
        #endregion ******************************************************************************************

        /**//// <summary>
        /// 初始化snake。设置好引用——与snake通信的对象的引用
        /// </summary>
        /// <param name="drawingPanel"></param>
        /// <param name="timer"></param>
        public Snake(Panel drawingPanel, System.Timers.Timer timer)
        ...{
            drawingPanel.Paint += new PaintEventHandler(drawingPanel_Paint);
            this.graphics = drawingPanel.CreateGraphics();
            
            AppendBlock(new Block(3, 1));
            AppendBlock(new Block(2, 1));
            AppendBlock(new Block(1, 1));// 这样初始化块，暗示了初时方向为向右

            drawingPanel.Invalidate();   // 已经有块了，绘制他们

            this.timer = timer;
        }


        /**//// <summary>
        /// 响应paint消息。先绘制背景，再绘制所有块
        /// </summary>
        void drawingPanel_Paint(object sender, PaintEventArgs e)
        ...{
            DrawAllBlocks();
        }



        public void Die()
        ...{
            if (status == SnakeStatus.RUNNING)
            ...{
                timer.Stop();
                graphics.Clear(Color.White);
                graphics.DrawString("Game Over", new Font("Arial", 16), new SolidBrush(Color.Black), new Point(0, 0));
                status = SnakeStatus.DEAD;
            }
        }

        public void Move(object source, System.Timers.ElapsedEventArgs e)
        ...{
            if (status == SnakeStatus.RUNNING)
            ...{
                isDirectionChangeAllowed = true;

                // move snake body according to direction

                // new block coordinates
                int NewHeadX=0;
                int NewHeadY=0;
                switch (direction)
                ...{
                    case Direction.UP:
                        NewHeadX = headBlock.X;
                        NewHeadY = headBlock.Y - 1;
                        break;
                    case Direction.DOWN:
                        NewHeadX = headBlock.X;
                        NewHeadY = headBlock.Y + 1;
                        break;
                    case Direction.LEFT:
                        NewHeadX = headBlock.X - 1;
                        NewHeadY = headBlock.Y;
                        break;
                    case Direction.RIGHT:
                        NewHeadX = headBlock.X + 1;
                        NewHeadY = headBlock.Y;
                        break;
                }

                if(NewHeadX<1||NewHeadX>50||NewHeadY<1||NewHeadY>20)
                ...{
                    Die();
                    return;
                }

                // 擦除和绘制
                tailBlock.Erase(graphics);
                tailBlock.SetPos(NewHeadX, NewHeadY);
                Rotate();
                headBlock.Draw(graphics);
            }
        }

        public void Pause()
        ...{
            if (status == SnakeStatus.RUNNING)
            ...{
                this.status = SnakeStatus.PAUSED;
                timer.Stop();
            } 
        }

        public void Resume()
        ...{
            if (status == SnakeStatus.PAUSED)
            ...{
                status = SnakeStatus.RUNNING;
                timer.Start();
            }
        }

        public void Turn(Direction newDirection)
        ...{
            if (status == SnakeStatus.RUNNING && isDirectionChangeAllowed)
            ...{
                if (newDirection == Direction.UP && this.direction == Direction.DOWN)
                ...{
                    return;
                }
                if (newDirection == Direction.DOWN && this.direction == Direction.UP)
                ...{
                    return;
                }
                if (newDirection == Direction.LEFT && this.direction == Direction.RIGHT)
                ...{
                    return;
                }
                if (newDirection == Direction.RIGHT && this.direction == Direction.LEFT)
                ...{
                    return;
                }

                this.direction = newDirection;
                isDirectionChangeAllowed = false;
            }
            if (status == SnakeStatus.INITIALIZED)
            ...{
                this.timer.Start();
                this.status = SnakeStatus.RUNNING;
                //this.isDirectionChangeAllowed = true;
                if (newDirection == Direction.LEFT)
                ...{
                    this.direction = Direction.RIGHT;
                }
                else
                ...{
                    this.direction = newDirection;
                }

                
            }
            if (status == SnakeStatus.DEAD)
            ...{
                // do nothing
            }
            if (status == SnakeStatus.PAUSED)
            ...{
                // do nothing
            }
        }


        
    }

    enum SnakeStatus
    ...{
        INITIALIZED, RUNNING, DEAD,PAUSED
    }

}

// block.cs
using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;

namespace snake
...{
    class Block
    ...{
        public Block Next;
        public Block Previous;

        private int x;
        private int y;

        public Block(int x, int y)
        ...{
            this.x = x;
            this.y = y;

            Next = null;
            Previous = null;
        }

        public int X
        ...{
            get
            ...{
                return x;
            }
        }

        public int Y
        ...{
            get
            ...{
                return y;
            }
        }

        public void SetPos(int x, int y)
        ...{
            this.x = x;
            this.y = y;
        }

        public void Draw(Graphics graphics)
        ...{
            
            graphics.FillRectangle(Brushes.Black, (x - 1) * 8, (y - 1) * 8, 8, 8);
            graphics.DrawRectangle(new Pen(Brushes.White), (x - 1) * 8, (y - 1) * 8, 8, 8);
        }

        public void Erase(Graphics grahics)
        ...{
            grahics.FillRectangle(Brushes.White, (x - 1) * 8, (y - 1) * 8, 8, 8);
        }
    }
}

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