C#实现绘制随机噪点和直线

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Bitmap image = new Bitmap(100, 22);
            Graphics g = Graphics.FromImage(image);
            try
            {
                //生成随机生成器
                Random random = new Random();
                //清空图片背景色
                g.Clear(Color.White);
                //画图片的背景噪音线
                for (int i = 0; i < 2; i++)
                {
                    Point tem_Point_1 = new Point(random.Next(image.Width), random.Next(image.Height));
                    Point tem_Point_2 = new Point(random.Next(image.Width), random.Next(image.Height));
                    g.DrawLine(new Pen(Color.Black), tem_Point_1, tem_Point_2);
                }

                //画图片的前景噪音点
                for (int i = 0; i < 100; i++)
                {
                    Point tem_point = new Point(random.Next(image.Width), random.Next(image.Height));
                    image.SetPixel(tem_point.X, tem_point.Y, Color.FromArgb(random.Next()));
                }

                //画图片的边框线
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                pictureBox1.Image = image;
            }
            catch
            {
            }
        }
    }

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                pictureBox1.Image = Image.FromFile(openFileDialog1.FileName);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            if (pictureBox1.Image != null)
            {
                Bitmap bt = new Bitmap(pictureBox1.Image);
                Graphics g = Graphics.FromImage(bt);
                g.DrawLine(new Pen(Color.Red, 40), new Point(0, bt.Height / 2), new Point(bt.Width, bt.Height / 2));
                g.DrawLine(new Pen(Color.Red, 40), new Point(bt.Width / 2, 0), new Point(bt.Width / 2, bt.Height));
                g.DrawLine(new Pen(Color.Red, 40), new Point(0, 0), new Point(bt.Width, bt.Height));
                g.DrawLine(new Pen(Color.Red, 40), new Point(0, bt.Height), new Point(bt.Width, 0));
                pictureBox1.Image = bt;
            }
        }
    }