TreeView连接数据

  string  connectionString  =   " Provider=Microsoft.Jet.OLEDB.4.0;User ID=Admin;Data Source=' "   +  HttpContext.Current.Server.MapPath( " ~/LHB_DataBase/rss.mdb " )  +   " ';Jet OLEDB:Engine Type=5;Jet OLEDB:Database Locking Mode=1;Jet OLEDB:Global Partial Bulk Ops=2;Jet OLEDB:Global Bulk Transactions=1;Jet OLEDB:Create System Database=False;Jet OLEDB:Encrypt Database=False;Jet OLEDB:Don't Copy Locale on Compact=False;Jet OLEDB:Compact Without Replica Repair=False;Jet OLEDB:SFP=False " ;
        OleDbConnection cn  =   new  OleDbConnection();
        OleDbCommand cmd  =   new  OleDbCommand();

         private   void  TreeViewOpeartor()
         ... {
             this .TreeView1.Nodes.Clear();
             string  OledbString  =   " select * from categories  " ;
            DataTable rss_Url  =   this .GetRss_Url();
            cn.ConnectionString  =  connectionString;
            cn.Open();
            cmd.Connection  =  cn;
            cmd.CommandText  =  OledbString;
            OleDbDataReader dda  =  cmd.ExecuteReader();
             while (dda.Read())
             ... {
                TreeNode theNode  =   new  TreeNode ();
                theNode.Text  =  dda[ " categoryname " ].ToString();
                theNode.NodeData  =  dda[ " ID " ].ToString();
                 this .TreeView1.Nodes.Add(theNode);
                DataRow[] urls  =  rss_Url.Select( " categoryID= "   +  dda[ " ID " ].ToString());
                 for ( int  i  =   0  ; i  <  urls.Length ; i ++ )
                 ... {
                    Microsoft.Web.UI.WebControls.TreeNode node  =   new  Microsoft.Web.UI.WebControls.TreeNode();
                    node.Text  =  urls[i][ " Rss_name " ].ToString();
                    node.Target  =  urls[i][ " Id " ].ToString();
                    node.NodeData  =  urls[i][ " ID " ].ToString();
                    theNode.Nodes.Add(node);
                }
            }
            dda.Close();
            cn.Close();
        }

    
         private  DataTable GetRss_Url()
         ... {
            cn.ConnectionString  =  connectionString ;
            OleDbDataAdapter dda  =   new  OleDbDataAdapter( " select * from rss where releasetoweb=1  " ,cn);
            DataTable dt  =   new  DataTable();
            dda.Fill(dt);
             return  dt;
        }