private void panel1_Paint(object sender, PaintEventArgs e) { Panel pl = (Panel)sender; Pen mpen = new Pen(Color.Red); mpen.Width = 1; e.Graphics.DrawLine(mpen, new Point(0, 0), new Point(0 ,pl.Height)); e.Graphics.DrawLine(mpen, new Point(0, 0), new Point(pl.Width, 0)); e.Graphics.DrawLine(mpen, new Point(0, 0), new Point(0, pl.Height)); e.Graphics.DrawLine(mpen, new Point(0, 0), new Point(0, pl.Height))； } 有的线条可能绘不出来，因为所绘制的线条的位置落在了panel里面
