TreeView树节点的直接操作

//在树上添加节点
    private void insertNode(string id) {

        if (ddl_PurType.SelectedIndex == 0)
        {
            tv_PurModel.Nodes[0].ChildNodes.Add(new TreeNode(this.tb_ModName.Text,id));
        }
        else {
            string path = "";
            if (ddl_ModelType.SelectedIndex == 0)
            {
                 path = "0/" + this.ddl_PurType.SelectedValue;
            }
            else {
                 path = "0/" + this.ddl_PurType.SelectedValue + "/" + this.ddl_ModelType.SelectedValue;
            }

            TreeNode tn = new TreeNode();
            tn = tv_PurModel.FindNode(path);  //根据path找到指定的节点
            tn.ChildNodes.Add(new TreeNode(this.tb_ModName.Text, id));
            tn.PopulateOnDemand = false;
        }
    }
 //在树上删除节点
    private void deleteNode()
    {
        string nodePath = this.tv_PurModel.SelectedNode.Parent.ValuePath;
        //ValuePath指的是根节点到当前节点的路径（根据节点的value值连起来的字符串，以0开始，以"/"分隔）
        this.tv_PurModel.FindNode(nodePath).ChildNodes.Remove(this.tv_PurModel.SelectedNode);
    }
 //在树上更新信息
    private void editNode() {
        this.tv_PurModel.SelectedNode.Text = this.tb_ModName.Text;
    }