G++版验证码

private void picString_Click(object sender, EventArgs e)
        {
            Random r = new Random();

            string strNumber = "";

            for (int i = 0; i < 5; i++)
            {
                int num = r.Next(10);

                //把随机数存到字符串中
                strNumber += num;
            }

            //位图来存放图片
            //设置位图大小
            Bitmap bm = new Bitmap(252, 213);
            //创建对象
            Graphics g = Graphics.FromImage(bm);
            //画验证码
            //五种字体
            string[] fontName = new string[] { "幼圆", "宋体", "隶书", "仿宋", "楷体" };
            //颜色
            Color[]color=new  Color[]{Color.Red ,Color.Black  ,Color.White,Color .Blue ,Color .Pink };

            for (int i = 0; i < 5; i++)
            {
                Point point = new Point(i * 120, 0);
                //随机的字体、颜色；大小40磅
                g.DrawString(strNumber, new Font(fontName [i],
                    40), new SolidBrush (color [i]),  point);
            }

            for (int i = 0; i < 103; i++)
            {
                Point p_1 = new Point(r.Next(bm.Width)/2, r.Next(bm.Height)/2);
                
                Point p_2 = new Point(r.Next(bm.Width), r.Next(bm.Height)/2);
                //画线（线条颜色为灰色，起点为 （p_1, p_2)
                g.DrawLine(new Pen(Brushes.Gray), p_1, p_2);
            }

            for (int i = 0; i < 1510; i++)
            {
                //设置点，颜色为yellow
                Point p = new Point(r.Next(bm.Width), r.Next(bm.Height));
                bm.SetPixel(p.X, p.Y, Color.Yellow);

            }
            //画验证码
            picString.Image = bm;
            
        }