运算符后缺少操作数解决思路

dv = new DataView(dt);        //筛选(相当于select * from tabMenu where menuParentID = 传入的 parentID)            dv.RowFilter = "[Privilege_ID]" + parentID;        //用foreach遍历dv            foreach (DataRowView row in dv)        {            //第一次加载时为空                if (node == null)            {                //创建根节点                    TreeNode root = new TreeNode();                //必须与数据库的对应                    root.Text = row["Description"].ToString();                root.Value = row["Parent_id"].ToString();                //添加根节点                    this.TreeView1.Nodes.Add(root);                //递归调用方法本身                    CreateTree(int.Parse(row["Parent_id"].ToString()), root, dt, treeView);            }            else            {                //添加子节点                    TreeNode childNode = new TreeNode();                childNode.Text = row["Description"].ToString();                childNode.Value = row["Parent_id"].ToString();                node.ChildNodes.Add(childNode);                CreateTree(int.Parse(row["Parent_id"].ToString()), childNode, dt, treeView);            }        }