如何按这个窗体高度变化,改变TREEVIEW的高度?

  private void MDI_Form_Load(object sender, EventArgs e)
        {
            Frm_Left frm_left1 = new Frm_Left();
            frm_left1.MdiParent = this;
            frm_left1.FormBorderStyle = FormBorderStyle.None;
            frm_left1.Width = 150;
            frm_left1.Height = this.Height - 42;
            frm_left1.Show();



        }

        private void MDI_Form_Resize(object sender, EventArgs e)
        {
            
        }