Question

C#里怎么在一个图片上面画线

单击按钮后picturebox里加载一副图片后，需要在图片的某个位置显示出红线，现在就是不知道怎么在图片上画线

Answer 1

  private void button1_Click(object sender, EventArgs e)
        {
            Graphics g = this.pictureBox1.CreateGraphics();
            Pen p = new Pen(Color.Red);
            g.DrawEllipse(p, 0, 0, 100, 100);
        }

Answer 2

using(Graphics g = Graphics.FromImage(pictureBox1.Image))
g.DrawLine(new Pen(Color.Red),0,0,30,30);//坐标
pictureBox1.Refresh();