treeView 與數據庫的操作

 數據庫字段 ID（自動增長列），Name（節點名稱),F_ID（父節點ID，父節點爲0)

private void Form4_Load(object sender, EventArgs e)
        {
            get_fujiedian();
        }

        //根菜單
        public void get_fujiedian()
        {
            DataTable dt = cla.select_table2_2();//調用SQL語句
            DataRow[] rows = dt.Select("F_ID=0");//添加SQL條件
            foreach (DataRow dr in rows)//循環賦值給DataRow
            {
                TreeNode node = new TreeNode();
                node.Tag = dr;
                node.Text = dr["Name"].ToString();
                treeView1.Nodes.Add(node);
                get_zijiedian(node);
            }
        }
        //得子節點
        public void get_zijiedian(TreeNode fnode)
        {
            DataTable dt = cla.select_table2_2();//調用SQL語句
            DataRow dr = (DataRow)fnode.Tag;//獲取根節點的ID
            int f_id = (int)dr["id"];
            DataRow[] rows = dt.Select("F_ID=" + f_id);//SQL語句加入條件進行查詢
            if (rows.Length == 0)//集合是否有值
            {
                return;
            }
            foreach (DataRow Drows in rows)
            {
                TreeNode node = new TreeNode();
                node.Tag = Drows;
                node.Text = Drows["Name"].ToString();
                //添加子節點              
                fnode.Nodes.Add(node);
                get_zijiedian(node);
            }
        }