TreeView的绑定与读取

/// <summary>
        /// 绑定TreeView
        /// </summary>
        public void BindTreeView()
        {
            BLL.GroupBLL GroupBll = new BLL.GroupBLL();
            DataTable GroupTable = GroupBll.GetGroup();
            //先绑定根节点
            for (int i = 0; i < GroupTable.Rows.Count; i++)
            {
                TreeNode NoteFather = new TreeNode(GroupTable.Rows[i]["Group"].ToString());
                this.TV_Power.Nodes.Add(NoteFather);
                this.TV_Power.Nodes[i].Value = GroupTable.Rows[i]["ID"].ToString();

                BLL.UserBLL UserBll=new BLL.UserBLL ();
                DataTable UserTable = UserBll.GetAllUser(Convert.ToInt32(GroupTable.Rows[i]["ID"]));
                //再绑定子节点
                for (int j = 0; j < UserTable.Rows.Count; j++)
                {
                    TreeNode NoteChild = new TreeNode(UserTable.Rows[j]["Name"].ToString());
                    this.TV_Power.Nodes[i].ChildNodes.Add(NoteChild);
                    this.TV_Power.Nodes[i].ChildNodes[j].ShowCheckBox = true;
                    this.TV_Power.Nodes[i].ChildNodes[j].Value = UserTable.Rows[j]["ID"].ToString();                  
                }
            }
        }

        StringBuilder Power = new StringBuilder();
        /// <summary>
        /// 读取TreeView节点的Value
        /// </summary>
        /// <param name="nodes"></param>
        /// <returns></returns>
        public string GetTreeViewValue(TreeNodeCollection nodes)
        {
            
            foreach (TreeNode tn in nodes)
            {
                if (tn.Checked && tn.ChildNodes.Count == 0)
                {
                    Power.Append(tn.Value + ",");
                }
                GetTreeViewValue(tn.ChildNodes);
            }
            return Power.ToString();
        }