笔记11：GDI 制作数字验证码

来源：互联网发布：人工智能可视化编辑：程序博客网时间：2024/06/10 15:20

大二学长让我学下GDI绘制验证码，然后自己就试了试了。找了点视频看了下。

　　　　现在会画直线，矩形，字符串，制作验证码

　　　　一、绘制一条直线

1         private void button1_Click(object sender, EventArgs e)2         {3             Graphics g = this.CreateGraphics();     //实例化4             Pen pen = new Pen(Color.Black);         //创建一只笔，颜色5             Point p1 = new Point(20, 30);           //两点确定一条直线6             Point p2 = new Point(100,200);7             g.DrawLine(pen,p1,p2);                  //画直线了8         }

　　　　二、绘制一个矩形，一个字符串

1         private void button2_Click(object sender, EventArgs e)2         {3             Graphics j = this.CreateGraphics();4             Pen pen = new Pen(Color.YellowGreen);5 6             j.DrawRectangle(pen,20,20,250,250);     //矩形7             j.DrawString("管星，还蛮不错的！",new Font("宋体",20,FontStyle.Bold),Brushes.Red,50,50);  //字符串8         }

　　　　三、制作验证码，和字符串升级版

 1         string yanzheng = ""; 2         public void huantu() 3         { 4             //随机生成一个，四个数字的字符串 5             Random r = new Random(); 6             string str = ""; 7             for (int i = 0; i < 4; i++) 8             { 9                 str = str + r.Next(0, 10).ToString();10             }11             yanzheng = str;12             //创建GDI对象13             Bitmap bmp = new Bitmap(100, 30);14             Graphics g = Graphics.FromImage(bmp);15             int n = 10;16             //将数字画进图片中，随机的字体，随机的颜色17             for (int i = 0; i < 4; i++)18             {19                 string[] fonts = { "微软雅黑", "宋体", "幼圆", "黑体", "仿宋" };20                 Color[] colors = { Color.PowderBlue, Color.Green, Color.Blue, Color.Black, Color.Red };21                 g.DrawString(str[i].ToString(), new Font(fonts[r.Next(0, 5)], 20, FontStyle.Bold), new SolidBrush(colors[r.Next(0, 5)]), n, 0);22                 n += 20;23             }24             //加干扰的点，25             for (int i = 0; i < 500; i++)26             {27                 Point p = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height));28                 bmp.SetPixel(p.X, p.Y, Color.Black);29             }30             //将图片镶嵌picturebox中31             pictureBox1.Image = bmp;32         }33         //看不清，换一张34         private void button2_Click(object sender, EventArgs e)35         {36             huantu();37         }38         private void button1_Click(object sender, EventArgs e)39         {40             if (yanzheng==this.textBox1.Text)41             {42                 MessageBox.Show("您输入的验证码正确！","消息提示");43             }44             else45             {46                 MessageBox.Show("您输入的验证码不正确！", "消息提示");47             }48         }49     }50 }

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