画箭头

using (Pen mypen = new Pen(Color.Black, 6))
            {
                mypen.StartCap = LineCap.DiamondAnchor;//设置起始箭头
                mypen.EndCap = LineCap.ArrowAnchor;//设置结尾箭头
                e.Graphics.DrawLine(mypen, 20f, 20f, 100f, 20f);//绘制直线  
            };//创建钢笔对象