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：
private void pictureBox1_Click(object sender, EventArgs e)
{
//创建GDI对象
Bitmap bmp = new Bitmap(,);
Graphics g = Graphics.FromImage(bmp); //产生随机数并画入图片中
Random r = new Random();
string str = "";
for (int i = ; i < ;i++ )
{
str += r.Next(,);
}
for (int i = ; i < ; i++)
{
Point p = new Point(i*,);
string[] fonts = { "微软雅黑", "宋体", "黑体", "隶书", "仿宋" };
Color[] colors = { Color.Yellow,Color.Blue,Color.Black,Color.Red,Color.Pink};
g.DrawString(str[i].ToString(),new Font(fonts[r.Next(,)],,FontStyle.Bold),new SolidBrush(colors[r.Next(,)]),p); } //画线
for (int i = ; i < ; i++)
{
Point p1 = new Point(r.Next(,bmp.Width),r.Next(,bmp.Height));
Point p2 = new Point(r.Next(,bmp.Width),r.Next(,bmp.Height));
g.DrawLine(new Pen(Brushes.Green),p1,p2);
} //将图片镶嵌到pictureBox中
pictureBox1.Image = bmp; }