用GDI+画验证码

Posted 2020-09-16 zhengwei_cq

1、新建一个窗体应用程序，在上面拖一个pictureBox对象，为其添加单击事件

2、创建GDI对象、产生随机数画入图片中、画线条、最后将图片到pictureBox中，代码如下：

 1  private void pictureBox1_Click(object sender, EventArgs e)
 2         {
 3             //创建GDI对象
 4             Bitmap bmp = new Bitmap(150,40);
 5             Graphics g = Graphics.FromImage(bmp);
 6 
 7            //产生随机数并画入图片中
 8             Random r = new Random();
 9             string str = "";
10             for (int i = 0; i < 5;i++ )
11             {
12                 str += r.Next(0,10);
13             }
14             for (int i = 0; i < 5; i++) 
15             {
16                 Point p = new Point(i*20,0);
17                 string[] fonts = { "微软雅黑", "宋体", "黑体", "隶书", "仿宋" };
18                 Color[] colors = { Color.Yellow,Color.Blue,Color.Black,Color.Red,Color.Pink};
19                 g.DrawString(str[i].ToString(),new Font(fonts[r.Next(0,5)],20,FontStyle.Bold),new SolidBrush(colors[r.Next(0,5)]),p);
20             
21             }
22 
23             //画线
24             for (int i = 0; i < 20; i++)
25             {
26                 Point p1 = new Point(r.Next(0,bmp.Width),r.Next(0,bmp.Height));
27                 Point p2 = new Point(r.Next(0,bmp.Width),r.Next(0,bmp.Height));
28                 g.DrawLine(new Pen(Brushes.Green),p1,p2);
29             }
30 
31             //将图片镶嵌到pictureBox中
32             pictureBox1.Image = bmp;
33 
34         }