小弟新人，下边的代码不理解，请大神予以指点，尤其是红色部分。多谢！！！
 private void 增加ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (dataForm == null)
            {
                dataForm = new DataForm();
                dataForm.DataPanelSelected += panelSelected;
                dataForm.WindowState = FormWindowState.Maximized;
                dataForm.MdiParent = this;
                dataForm.Visible = true;
            }
            dataForm.AddDataPanel();
        }
        private void panelSelected(object sender, DataPanel panel)
        {
            if (treeView1.Nodes.Count > 0)
            {
                recursiveSelect(treeView1.Nodes[0], panel.CurveDescriptions);
            }
        }
        private void recursiveSelect(TreeNode node, List<string> list)
        {
            if (list == null) return;
            if (node.Nodes.Count == 0)
            {
                if (list.Contains(node.Text) && !node.Checked)
                    node.Checked = true;
                else if (!list.Contains(node.Text) && node.Checked)