C# TreeView reads a simple database instance

using System;
using ;
using ;
using ;
using ;
using ;
using ;
using ;
using ;
using ;

 

namespace TreeView
{
    public partial class TreeView :
    {
        string connection = ["SQLconnection"].ToString();
        protected void Page_Load(object sender, EventArgs e)
        {
            select();
            CreateTree();
        }
        DataSet ds = new DataSet();
        public DataSet DataS(string sql, string tablename)
        {
            SqlConnection con = new SqlConnection(connection);
            SqlDataAdapter sqlda = new SqlDataAdapter(sql, con);
            (ds, tablename);
            return ds;
        }

//ParentMenu: parent node,
//Grade: Identify which level of node this is,
//Flag: Identify whether the flag is the end node, 1 is 0 is not,
//href: Link to
        public void select()
        {
            string sql = "select * from treeview";
            ds = DataS(sql, "test");
        }

        public void CreateTree()
        {
            try
            {
                DataTable dt = ["test"];
                SortedList sl = new SortedList();
                TreeNode tn = new TreeNode();
                if ( <= 0)
                {
= "empty";
                    = "";
                    = "";
                    = "";
                    = false;
                    = ;

                }
                else
                {
                    for (int i = 0; i < ; i++)
                    {
//Create parent node
                        if ([i]["Grade"].ToString() == "1")
                        {
                            TreeNode node = new TreeNode();
                            = [i]["MenuName"].ToString();
                            = [i]["MenuID"].ToString();
                            if ([i]["Flag"].ToString() == "1")
                            {
                                = [i]["href"].ToString();
                                = "_bank";
                            }
                            = false;
                            = ;
                            (, node);
                            tv_Method.(node);
                        }
                        else
                        {
//Find parent node
                            TreeNode ParentNod = (TreeNode)(([i]["ParentMenu"].ToString()));
//Create child nodes
                            TreeNode tnChild = new TreeNode();
                            = [i]["MenuName"].ToString();
                            = [i]["MenuID"].ToString();
                            if ([i]["Flag"].ToString() == "1")
                            {
                                = [i]["href"].ToString();
                                = "_bank";
                            }
                            = false;
                            = ;
                            (, tnChild);
                            (tnChild);
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
    }
}