在c＃winforms中使用paint方法时如何防止闪烁？

Code:

码：

private void panel1_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.DrawRectangle(Pens.White,
    e.ClipRectangle.Left,
    e.ClipRectangle.Top,
    e.ClipRectangle.Width - 1,
    e.ClipRectangle.Height - 1);
    base.OnPaint(e);
}
private void panel1_Paint(object s