1.画带箭头的线
Graphics g = new Graphics();
Pen p = new Pen( Color.White );
p.CustomStartCap = new System.Drawing.Drawing2D.AdjustableArrowCap((float)(p.Width * 3.5), (float)(p.Width * 6), true);
p.EndCap = LineCap.NoAnchor;
Point start0 = new Point( 0 , 0 );
Point start00 = new Point( 0 , 19);
g.DrawLine(p, start0, start00);