C# 中Treeview无限级目录实现

库表结构:

      后台代码:

    protected void Page_Load(object sender, EventArgs e)//页面打开时执行
    {
        if (!IsPostBack)
        {
            PopulateNodes(TreeView1.Nodes, 0);
        }
    }

    public DataTable GetTreeTable()//获得表
    {
        dbClient db = new dbClient();
        DataTable dt =  HttpContext.Current.Cache["Treeview"] as DataTable;//缓存表，保证速度
        string sql = "select id,pid,yhm from users";
        dt = db.getSQLTable(sql, "dt");  //获得表    
        return dt;
    }

    public void PopulateNodes(TreeNodeCollection nodes, Int32 intParentID)//节点展开
    {
        DataTable dt = GetTreeTable();
        String strExpression = String.Empty;
        strExpression = "[pid]=" + intParentID;
        System.Data.DataRow[] dr;
        dr = dt.Select(strExpression);
        for (Int32 i = 0; i <= dr.GetUpperBound(0); i++)
        {
            TreeNode tn = new TreeNode();
            tn.Text = dr[i]["yhm"].ToString().Trim();
            tn.Value = dr[i]["id"].ToString();
            tn.NavigateUrl = "Detail.aspx?>