TreeView的递归读取

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace CTERP
{
    public partial class FrmSysFunctionMenu : Form
    {
        public FrmSysFunctionMenu()
        {
            InitializeComponent();
        }

        LinkDataBase link = new LinkDataBase();
        DataSet dsFunctionMenu = null;
        private void FrmFunctionMenu_Load(object sender, EventArgs e)
        {
            dsFunctionMenu = new DataSet();
            tvFunctionMenu.Nodes.Add("ERP系统功能菜单");
            TreeNode rootNode = tvFunctionMenu.Nodes[0];
            CreateChildTree(-1, rootNode);
            rootNode.Expand();//展开根结点
        }

        //递归调用创建子树
        private void CreateChildTree(int nparentid, TreeNode currentNode)
        {
            using (SqlConnection sqlCONN = new SqlConnection("server=.;uid=sa;database=cterp"))
            {
                string strSelect = "select id,title,parentid,sortid from sy_menu_wds where parentid=" + nparentid + " order by sortid";
                SqlCommand sqlCMD = new SqlCommand(strSelect);
                sqlCMD.Connection = sqlCONN;
                sqlCONN.Open();
                using (SqlDataReader sqlDR = sqlCMD.ExecuteReader())
                {
                    while (sqlDR.Read())
                    {
                        TreeNode node = new TreeNode(sqlDR["title"].ToString().Trim());
                        CreateChildTree(int.Parse(sqlDR["id"].ToString().Trim()), node);  //递归出子节点 
                        currentNode.Nodes.Add(node);
                    }
                }
            } 
        }

    }
}