private void InitTree(TreeNodeCollection Nds,int parentid)
        {
            DataView dv = new DataView();
            TreeNode tmpNd = null;
            dv.Table = ds.Tables[0];
            dv.RowFilter = String.Format("parentid={0}", parentid);
            foreach (DataRowView drv in dv)
            {
                tmpNd = new TreeNode();
                tmpNd.Text = (string)drv["sortname"];//节点名称
                tmpNd.NavigateUrl = String.Format("?id={0}", drv["id"]);//节点URL
                //tmpNd.ImageUrl = ""; //节点图片
                if (parentid == 0)
                    tmpNd.Expanded = true;
                else
                    tmpNd.Expanded = false;
                Nds.Add(tmpNd);
                InitTree(Nds[Nds.Count - 1].ChildNodes, (int)drv["id"]);
            }
        }