DROPDOWNLIST无限树形菜单

public void GetSubClass(DataSet ds, int level, string parentid, string sign)
        {
            char nbsp = (char)0xA0;
            string lp = "";
            DataRow[] drr2 = ds.Tables[0].Select(" parentId='" + parentid + "' ");
            int index = 0;
            if (level == 0)
            {
                foreach (DataRow dr in drr2)
                {
                    index++;
                    lp = dr["name"].ToString().Insert(0, "|___");
                    DropDownList1.Items.Add(new ListItem(lp.PadLeft((lp.Length + 2), nbsp), dr["id"].ToString()));
                    if (index != drr2.Length)
                        GetSubClass(ds, level+1, dr["id"].ToString(), "1");
                    else
                        GetSubClass(ds, level+1, dr["id"].ToString(), "0");
                }
            }
            else
            {
                DataRow[] drr3 = ds.Tables[0].Select(" parentid='" + parentid + "' ");
                string[] fg = { "," };
                string ls = "";
                
                if (drr3 != null && drr3.Length > 0)
                {
                    foreach (DataRow dr2 in drr3)
                    {
                        int lslevel = level;
                        index++;
                        foreach (string ss in sign.Split(fg, StringSplitOptions.RemoveEmptyEntries))
                        {
                            if (lslevel == level)
                            {
                                if (ss == "1")
                                {
                                    lp = "|";
                                    lp = lp.PadLeft((lp.Length + 2), nbsp);
                                    lp = lp.PadRight((lp.Length + 10), nbsp);
                                }
                                else
                                {
                                    lp = " ";
                                    lp = lp.PadLeft((lp.Length + 2), nbsp);
                                    lp = lp.PadRight((lp.Length + 10), nbsp);
                                }
                                lslevel--;
                                if (lslevel == 0)
                                    lp = lp + "|___" + dr2["name"].ToString();
                            }
                            else
                            {
                                if (ss == "1")
                                {
                                    lp += "|";
                                    lp = lp.PadRight((lp.Length + 10), nbsp);
                                }
                                else
                                {
                                    lp = lp.PadRight((lp.Length + 11), nbsp);
                                }
                                lslevel--;
                                if (lslevel == 0)
                                    lp = lp + "|___" + dr2["name"].ToString();
                            }

                        }
                        if (index != drr3.Length)
                        {
                            DropDownList1.Items.Add(new ListItem(lp, dr2["id"].ToString()));

                            GetSubClass(ds, level+1, dr2["id"].ToString(), sign + ",1");
                        }
                        else
                        {
                            DropDownList1.Items.Add(new ListItem(lp, dr2["id"].ToString()));

                            GetSubClass(ds, level+1, dr2["id"].ToString(), sign + ",0");
                        }

                    }
                }
            }
        }
        protected void qxa()
        {
            Maticsoft.BLL.webClass classwc = new Maticsoft.BLL.webClass();
            DataSet ds;
            //string lp="";  
            //int index = 0;  
            //char nbsp = (char)0xA0;  
            ds = classwc.GetList("  ");
            DropDownList1.Items.Clear();
            DropDownList1.Items.Add(new ListItem("根栏目", "0"));
            if (ds != null && ds.Tables.Count > 0 && ds.Tables[0] != null && ds.Tables[0].Rows.Count > 0)
            {
                //DataRow[] drr2 = ds.Tables[0].Select(" parentId=0  ");  
                GetSubClass(ds, 0, "0", "");
                //foreach (DataRow dr in drr2)  
                //{  
                //    index++;  
                //    lp = dr["name"].ToString().Insert(0, "|___");  
                //    DropDownList1.Items.Add(new ListItem(lp.PadLeft((lp.Length + 2),nbsp), dr["id"].ToString()));  
                //    DataRow[] drr3 = ds.Tables[0].Select(" parentid=" + dr["id"].ToString() + " ");  
                //    if (drr3 != null && drr3.Length > 0)  
                //    {  
                //        foreach (DataRow dr2 in drr3)  
                //        {  
                //            if (index != drr2.Length)  
                //            {  
                //                lp = "|";  
                //                lp = lp.PadLeft((lp.Length + 2), nbsp);  
                //                lp = lp.PadRight((lp.Length + 8), nbsp);  
                //                lp = lp + "|___" + dr2["name"].ToString();  
                //            }  
                //            else  
                //            {  
                //                lp = " ";  
                //                lp = lp.PadLeft((lp.Length + 2), nbsp);  
                //                lp = lp.PadRight((lp.Length + 8), nbsp);  
                //                lp = lp + "|___" + dr2["name"].ToString();  
                //            }  
                //             DropDownList1.Items.Add(new ListItem(lp, dr2["id"].ToString()));  
                //        }  
                //    }  

                //}  
            }
        }