动态加载TreeView

using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;
using System.Data.SqlClient;

public partial class _Default : System.Web.UI.Page
{
  public static   DataTable dt;
    protected void Page_Load(object sender, EventArgs e)
    {
        SqlConnection cn = new SqlConnection("Persist Security Info=False;User ID=sa;Initial Catalog=MyOffice;Data Source=.");
        cn.Open();
        SqlCommand cm = new SqlCommand("select * from sysfun",cn);
        SqlDataAdapter sda = new SqlDataAdapter(cm);
        DataSet ds = new DataSet();
        sda.Fill(ds, "ss");
        dt= ds.Tables["ss"];
        DataRow[] dr = dt.Select("ParentNodeId=0");
        int count=dr.Length ;
        for (int i = 0; i < count;i++ )
        {
            TreeNode tn = new TreeNode(dr[i][1].ToString());
            string name=dr[i][0].ToString ();
            this.TreeView1.Nodes.Add(tn);
            dire(tn,name );
           
        }
   
    }
    public void dire(TreeNode tn, string tt)
    {
        DataRow[] dr = dt.Select("ParentNodeId="+tt);
        if (dr.Length == 0)
            return;
        int count = dr.Length;
        for (int i = 0; i < count; i++)
        {
            TreeNode tnn = new TreeNode(dr[i][1].ToString ());
            string ming = dr[i][0].ToString();
            tn.ChildNodes.Add(tnn );
            dire(tnn,ming);
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        this.TreeView1.Visible = false;
        string[] dir = Directory.GetDirectories("e:/");
     // string []dirx=  Directory.("e:/");
        foreach (string t in dirx  )
        {
            TreeNode tn = new TreeNode(t);
            this.TreeView2.Nodes.Add(tn);
        }
    }
}