PictureBox 双缓冲防止闪屏

 Bitmap bm = new Bitmap(this.pbTraffic.Image);
                BufferedGraphicsContext current = BufferedGraphicsManager.Current;
                BufferedGraphics buf = current.Allocate(pbTraffic.CreateGraphics(), pbTraffic.DisplayRectangle);
                buf.Graphics.Clear(pbTraffic.BackColor);
                buf.Graphics.DrawImage(bm, mx, my, pbTraffic.Width, pbTraffic.Height);
                buf.Render(pbTraffic.CreateGraphics());