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         }

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         }

 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             else
45             {
46                 MessageBox.Show("您输入的验证码不正确！", "消息提示");
47             }
48         }
49     }
50 }