public void node_MouseHover(object sender, System.EventArgs e)
        {
            Label node = (Label)sender;
            if (node.ForeColor == Color.Black)
            {
                node.ForeColor = Color.Yellow;
                node.Font = new Font("宋体", 4.55f);
                node.Size = new Size(7, 7);
                AnchorDistance(node);
            }
            this.toolTip1.SetToolTip(node, node.Tag.ToString()); C#无线传感器网络节点定位系统设计(14):http://www.youerw.com/jisuanji/lunwen_2795.html