c#写的折叠菜单

自己写的一个C#的折叠菜单，可能写的很麻烦。。。仿WINDOWS那种吧，点一个按钮就会隐藏显示下面的菜单，其他菜单不变，以上

 

        //两个LIST用来放BUTTON和PANEL

        List<Button> listbut = new List<Button>();
        List<Panel> listpan = new List<Panel>();

        //这里就不多写了
        private void Form1_Load(object sender, EventArgs e)
        {
            button3.Top = 0;
            panel3.Top = button3.Top + button3.Height;
            button4.Top = panel3.Top + panel3.Height;
            panel4.Visible = false;
            button5.Top = button4.Top + button4.Height;
            panel5.Visible = false;
            listbut.Add(button3);
            listbut.Add(button4);
            listbut.Add(button5);
            listpan.Add(panel3);
            listpan.Add(panel4);
            listpan.Add(panel5);
        }
 //实现折叠的方法
 private void btnpanv(Button btn)
        {
            int num1 = int.Parse(btn.Name.Substring(6));//这里的裁剪根据按钮名字来写
            foreach (Button bt in listbut)
            {
                int num2 = int.Parse(bt.Name.Substring(6));//这里的裁剪根据按钮名字来写
                int top = 0;
                foreach (Panel pl in listpan)
                {
                    int pnum = int.Parse(pl.Name.Substring(5));这里的裁剪根据PANEL名字来写
                    if (num2 > pnum && num2 != 3)//此处的3是最上的按钮编号
                    {
                        if (pl.Visible == true)
                        {
                            top += this.button3.Height + pl.Height;
                        }
                        else
                        {
                            top += this.button3.Height;
                        }
                    }
                    else if (num2 == pnum)
                    {
                        if (num2 == num1)
                        {
                            if (pl.Visible == true)
                            {
                                pl.Visible = false;
                            }
                            else
                            {
                                pl.Visible = true;
                            }
                        }
                        pl.Top = top + bt.Height;
                        break;
                    }
                }
                bt.Top = top;
            }
        }
        private void button3_Click(object sender, EventArgs e)
        {
            btnpanv(button3);
        }

        private void button4_Click(object sender, EventArgs e)
        {
            btnpanv(button4);
        }

        private void button5_Click(object sender, EventArgs e)
        {
            btnpanv(button5);
        }