[c# 初学-窗体] 设计一个可收缩的侧边导航栏

一个简单的窗体界面，左侧导航栏按钮可收缩，类似windows界面。
效果如下图，一时没找到上下箭头图标，以其他图标代替初学者，欢迎各位前辈多多指教。操作过程：
新建一个窗体应用程序
放入相应的button和picturebox控件、label控件,
一个imagelist控件，将需要用的图标放进去双击picturebox控件，程序如下：
namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
       
        public Form1()
        {
            InitializeComponent();
        }
        bool k,l,m;//根据bool状态用if来确认打开还是收缩
        private void Form1_Load(object sender, EventArgs e)
        {
            
            pictureBox1.Image = imageList1.Images[0];//需要在窗体中为imageList1设置两幅用来切换的图片
            pictureBox2.Image = imageList1.Images[0];
            pictureBox3.Image = imageList1.Images[0];
            k = true;l = true;m = true;//设置标志位
        }
        int i = 80;//定义一个值对控件的高度进行递增递减，数值不要太小
        
        private void pictureBox1_Click(object sender, EventArgs e)
        {
            if (k == true)
            {
                pictureBox1.Visible = true;//可见状态
                button1.Visible = true;//可见状态
                label1.Visible = false;//不可见状态
                label2.Visible = false;//不可见状态
                pictureBox2.Top -= i;//控件提升至适当的高度
                button2.Top -= i;
                label3.Top -= i;
                label4.Top -= i;
                pictureBox3.Top -= i;
                button3.Top -= i;
                label5.Top -= i;
                label6.Top -= i;
                pictureBox1.Image = imageList1.Images[1];//切换图片
                k = false;//设置标志，方便if识别
            }            else
            {
                pictureBox1.Visible = true;//可见状态
                button1.Visible = true;//可见状态
                label1.Visible = true;//可见状态
                label2.Visible = true;//可见状态
                pictureBox2.Top += i;//控件降低至适当的高度
                button2.Top += i;
                label3.Top += i;
                label4.Top += i;
                pictureBox3.Top += i;
                button3.Top += i;
                label5.Top += i;
                label6.Top += i;
                pictureBox1.Image = imageList1.Images[0];//切换图片
                k = true;//设置标志，方便if识别
            }
            }
        private void pictureBox2_Click(object sender, EventArgs e)
        {
            if (l == true)
            {
                pictureBox2.Visible = true;
                button2.Visible = true;
                label3.Visible = false;
                label4.Visible = false;
                pictureBox3.Top -= i;
                button3.Top -= i;
                label5.Top -= i;
                label6.Top -= i;
                pictureBox2.Image = imageList1.Images[1];
                l = false;
            }            else
            {
                pictureBox2.Visible = true;
                button2.Visible = true;
                label3.Visible = true;
                label4.Visible = true;
                pictureBox3.Top += i;
                button3.Top += i;
                label5.Top += i;
                label6.Top += i;
                pictureBox2.Image = imageList1.Images[0];
                l = true;            }
        }
    }
}