1、628概念实训吃金豆游戏概念实训(吃金豆游戏)1代理和事件一、 代理(delegate)1、 代理概念 是一种将方法作为对象封装起来的引用数据类型,一个代理变量可以指向一个方法。(1)定义一个名为OpHandler的代理类型。 delegate double OpHandler(double x,double y);(2)创建一个代理变量h1; class Calc public static double Add(double x,double y)return x+y; public double Sub(double x,double y)return x-y; OpHandler h1
2、 = Calc.Add; /h1指向Add方法(3)通过代理变量h1调用它指向的方法 double result; result = h1(3,4); /调用Add方法 h1 = new Calc().Sub; result = h1(3,4); /调用Sub方法2、 代理作为方法的参数 class MathOp private double left; private double right; public MathOp(double left,double right) this.left = left; this.right = right; public double GetResu
3、lt(OpHandler op) return op(left,right); class App public static void Main() MathOp m1 = new MathOp(3,4); double result = m1.GetResult(Calc.Add); Console.WtriteLine(“result = 0”,result); 3、 代理变量作为类的一个数据成员class MathOp public OpHandler op; /op是代理变量 private double first; private double second; public Ma
4、thOp(double first,double second) this.first = first; this.second = second; op = null; public double Invoke() if(op=null) /如果有方法注册委托变量op throw new Exception(); return op(first,second); /通过委托来调用方法 class App public static void Main() MathOp m1 = new MathOp(3,4); m1.op = Calc.Add; double result = m1.Inv
5、oke(); Console.WtriteLine(“result = 0”,result); 4、 多播代理在 C# 中,代理是“多播”的,这表示它可同时指向一个以上的方法。多播代理将维护一个方法列表。当调用该代理时,将会按FIFO顺序调用列表中的所有方法。public delegate void GreetingDelegate(string name); class GreetingManager public GreetingDelegate say;public void GreetPeople(string name) if(say!=null) say(name);class A
6、pppublic static void EnglishGreeting(string name) Console.WriteLine(Morning, + name); /英文问候public static void ChineseGreeting(string name) Console.WriteLine(早上好, + name); /中文问候 public static void Main() GreetingManager gm = new GreetingManager ();gm.say = EnglishGreeting;gm.say += ChineseGreeting; /
7、用+=合并两个代理gm.GreetPeople(“Marry”); /也可以直接gm.say(“Marry”)调用委托 注:同样用-=可以删除一个代理。二、 事件(event)将代理封装起来就成了事件,事件对外是公开的,而它所对应的代理是私有的。事件可以看作是受限的代理。因此事件也可以绑定(注册)一个方法,但不能通过=,只能通过+=进行。事件最常见的用途是用于窗体编程,当发生像点击按钮、移动鼠标等事件时,对应的方法执行,以响应该事件。例1:将上例的GreetingDelegate代理封装成MakeGreet的事件,代码如下:public delegate void GreetingDelega
8、te(string name);class GreetingManager /* 将代理GreetingDelegate封装成事件MakeGreet*/public event GreetingDelegate MakeGreet; public void GreetPeople(string name) if(MakeGreet!=null) MakeGreet(name); /调用事件class Apppublic static void EnglishGreeting(string name) Console.WriteLine(Morning, + name); /英文问候public
9、 static void ChineseGreeting(string name) Console.WriteLine(早上好, + name); /中文问候 public static void Main() GreetingManager gm = new GreetingManager ();gm.MakeGreet = EnglishGreeting; /编译错误,不允许用=注册方法gm.MakeGreet += ChineseGreeting; gm.GreetPeople(“Marry”); /*不可以直接gm. MakeGreet (“Marry”)调用事件,只能在定义MakeG
10、reet的类中调用事件。 */ 例2: 类Button在GUI中代表按钮,在Button类中定义了一个Click事件,它是对代理EventHandler的封装。(1)EventHandler代理的定义如下:delegate void EventHandler(object sender,EventArgs e); (2)Click事件定义如下: event EventHandler Click; Button btnOK = new Button(); /实例化一个名btnOk的按钮 btnOK.Click += ClickProcess; /为它的Click事件注册ClickProcess方
11、法。 则当单击btnOK按钮时,ClickProcess方法被调用以响应该单击事件。 2窗体和按钮一、窗体(Form类)1、Form类是所有高级窗口的基类。2、设置Form属性 如: (Text, Location, Size, Name) (FormBorderStyle, BackColor, StartPosition) (MaximunBox, MinimunBox, ControlBox)等。二、按钮控件(Button类)1、属性:(Text, Name, Enabled, )2、方法: Show(),Hide(),Focus(),Invalidate()3、事件: ClickGUI
12、应用程序的例子:1)生成并显示一个标题为Hello的空白窗体:class MyForm:Form public MyForm() this.Text = “Hello”;class WinApp public static void Main() Application.Run(new MyForm();2)在窗体中增加一个按钮,按钮标题为OK,修改MyForm类:class MyForm:Form private Button btnOK; public MyForm() btnOK = new Button(); btnOK.Text = “OK”; this.Text = “Hello”
13、;this.Controls.Add(btnOK);运行程序,单击OK按钮,看看有没有什么发生?3)为OK按钮注册Click事件,当单击OK时,按钮的背景色变红。修改MyForm类:class MyForm:Form private Button btnOK; public MyForm() btnOK = new Button(); btnOK.Text = “OK”; btnOK.Click+= ClickProcess; /注册click事件this.Text = “Hello”;this.Controls.Add(btnOK);public void ClickProcess(obje
14、ct sender,EventArgs e) btnOK.BackColor = Color.Red;运行程序,单击OK按钮,看看发生了什么?3GDI编程GDI(Graphics Device Interface)为开发者提供了一组实现与各种设备进行交互的类库,它在开发人员与设备之间起到了一个重要的中介作用。GDI包括三个部分: 二维矢量图形绘制 图像处理 文字显示一、 Graphics类该类封装了GDI的绘图表面,Windows窗体中所有的绘图操作都必须通过Graphics类进行。1、 创建或获取Graphics对象法一:Graphics g = 控件.CreateGraphics();法二
15、:通过窗体或控件的Paint事件来获取。 以窗体为例:paint事件在窗体的任何部分需要重绘时发生。 引发paint事件的情况有:(1) 窗体首次运行时(2) 覆盖窗体的其他窗体移开时(3) 窗体本身移动,或大小改变时Private void Form1_Paint(object sender,PaintEventArgs e) Graphics g = e.Graphics; g.DrawLine(); 2、 用Graphics类提供的各种方法: 绘图 显示文本 操作和显示图像DrawLine()DrawEllipse()DrawRectangle()DrawImage()DrawStrin
16、g()FillEllipse()二、 创建画笔和画刷1、 Pen类创建指定颜色和线宽画笔对象 Pen p1 = new Pen(Color.Red); /设置颜色 Pen p2 = new Pen(Color.Black,10); /设置颜色和线宽 Pen p3 = Pens.Blue; /Pens类中预定义的画笔2、 画刷Brush抽象类SolidBrush、HatchBrush等是Brush类的子类 Brush b1 = new SolidBrush(Color.Red); Brush b2 = new HachBrush(HatchStyle.Cross,Color.Blue,Color
17、.Yellow); Brush b3 = Brushes.Red; /Brushes类中预定义的画刷三、 x0(0,0)y0widthheight(x,y)坐标系统(1)画椭圆 g.DrawEllipse(Pen pen,int x,int y,int width,int height);(2)画扇形 g.DrawArc(Pen pen,int x,int y,int width,int height,int startAngle,int degree);(3)显示文字g.DrawString(“Hello”,this.Font,Brushes.Red,20,20);g.DrawString(
18、“Hello”,new Font(“宋体”,30,FontStyle.Bold),Brushes.Red);例一:在窗体中绘制如下的图形private void Form1_Paint(object sender, PaintEventArgs e) Graphics g = e.Graphics; float diameter=50; g.DrawLine(Pens.Red, 0, 0, this.ClientSize.Width, this.ClientSize.Height); g.DrawLine(Pens.Blue), 0, this.ClientSize.Height, this.
19、ClientSize.Width, 0); g.DrawEllipse( Pens.Black, (this.ClientSize.Width - diameter)/2, (this.ClientSize.Height - diameter)/2, diameter, diameter ); /窗体大小改变时触发Resize事件 private void Form1_Resize(object sender, EventArgs e) this.Invalidate(); /使窗体或控件无效,并人为引发其Paint事件,进行重绘 this.Update(); 例二:在面板中绘制如下的图形:要
20、求:在文本框中输入行和列,单击clear按钮,对应位置的小金豆被清除。法一:直接在面板中绘图private void panel1_Paint(object sender, PaintEventArgs e) Graphics g = e.Graphics; int r, c; r = c = 8; /r行,c列 int h, w; /每个方块的高度和宽度 w = panel1.Width / c; h = panel1.Height / r; for (int i = 0; i r; i+) for (int j = 0; j c; j+) g.DrawRectangle(Pens.Blue
21、, j * w, i * h, w, h); g.FillEllipse( Brushes.Yellow, j * w + (w - 20) / 2, i * h + (h - 20) / 2, 20, 20); private void btnClear_Click(object sender, EventArgs e) int r = int.Parse(txtRow.Text); int c = int.Parse(txtCol.Text); int w = panel1.Width / 8; int h = panel1.Height / 8; Graphics g = panel1.
22、CreateGraphics(); Brush b1 = new SolidBrush(panel1.BackColor); g.FillEllipse(b1, c * w + (w - 20) / 2, r *h +(h - 20) / 2, 20, 20); 法二:将一个方块封装成一个Cell对象。Cell-r:int /行-c:int /列-w:int /宽度-h:int /高度+Cell(int r,int c,int w,int h);+Draw(Graphics g):void+Clear(Graphics g,Color foreColor):voidclass Cell pri
23、vate int r,c,w,h; public Cell(int r, int c, int w, int h) this.r = r; this.c = c; this.w = w; this.h = h; public void Draw(Graphics g) int x, y; x = w * c; y = h * r; g.DrawRectangle(Pens.Blue, x, y, w, h); g.FillEllipse(Brushes.Yellow, x + (w - 20) / 2, y + (h - 20) / 2, 20, 20); public void Clear(
24、Graphics g, Color foreColor) int x, y; x = w * c; y = h * r; g.FillEllipse(new SolidBrush(foreColor), x, y, w, h); 在Form1类中如下定义:private Cell, cellArr; public Form1() InitializeComponent(); cellArr = new Cell8, 8; for (int i = 0; i 8; i+) for (int j = 0; j 8; j+) cellArri, j = new Cell(i, j, panel1.W
25、idth / 8, panel1.Height / 8); private void panel1_Paint(object sender, PaintEventArgs e) for (int i = 0; i cellArr.GetLength(0); i+) for (int j = 0; j cellArr.GetLength(1); j+) cellArri, j.Draw(e.Graphics); private void btnClear_Click(object sender, EventArgs e) int r, c; r = int.Parse(txtRow.Text);
26、 c = int.Parse(txtCol.Text); cellArrr, c.Clear(panel1.CreateGraphics(), panel1.BackColor); 例三:设计一个pacman,要求:(1)可以通过按钮控制它的上下左右运动。Cell-r:int /行-c:int /列-w:int /宽度-h:int /高度+Cell(int r,int c,int w,int h);+Draw(Graphics g):void+Clear(Graphics g,Color foreColor):void+abstract DrawImage(Graphics g,int x,i
27、nt y):voidPacman-dir:Directoin /Direction枚举四种方向+Pacman(int r,int c,int w,int h,Direction dir);+Draw(Graphics g):void+Move():void+override DrawImage(Graphics g,int x,int y):void代码参考:enum DirectionUp,Down,Left,Right;class Pacman:Cell protected Direction dir; public Pacman(int r,int c,int w,int h,Direc
28、tion dir):base(r,c,w,h) this.dir = dir; public override void DrawImage(Graphics g, int x, int y) g.FillEllipse(Brushes.Black, x + (w - 20) / 2, y + (h - 20) / 2, 20, 20); public void Move() switch (dir) case Direction.Up: r-; break; case Direction.Down: r+; break; case Direction.Left: c-; break; cas
29、e Direction.Right: c+; break; public Direction Dir get return dir; set dir = value; public partial class Form1 : Form private Pacman myPacman; public Form1() InitializeComponent(); myPacman = new Pacman( 0, 0, panel1.Width / 16, panel1.Height / 8, Direction.Right ); private void panel1_Paint(object sender, PaintEventArgs e) myPacman.Draw(e.Graphics); private void btnUp_Click(object sender, EventArgs e) myPacman.Dir = Direction.Up; myPacman.Move(
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