Tree view recursive

[neelmukhopadhya]

I have tried for a recursive tree.

Please help me.

Here is my code:

private void PopulateReport()
        {
            List<ListItems> siteData = new List<ListItems>();
            DataTable dt = GetAllData4();

            foreach (DataRow dr in dt.Rows)
            {
               siteData.Add(new ListItems(int.Parse(dr["MainId"].ToString()),dr["MainName"].ToString(),int.Parse(dr["SecondId"].ToString()),dr["SecondName"].ToString(),int.Parse(dr["ThirdId"].ToString()),dr["ThirdName"].ToString()));
            }
            var nodes = siteData.Find(x => x.MainId ==int.Parse(dt.Rows[0]["MainId"].ToString()));
            if (nodes != null)
            {
                RadTreeNode radTreeNode = new RadTreeNode(nodes.MainName, nodes.MainId.ToString());
                radTree1.Nodes.Clear();
                radTree1.Nodes.Add(radTreeNode);
                BindTree(siteData, radTreeNode);
            }
        }

        private void BindTree(IEnumerable<ListItems> list, RadTreeNode parentNode)
        {
            var nodes = list.Where(x => parentNode == null ? x.MainId == 0 : x.MainId ==int.Parse(parentNode.Value));
            foreach (var node in nodes)
            {
                RadTreeNode radTreeNode = new RadTreeNode(node.MainName, node.MainId.ToString());
                if (parentNode == null)
                {
                    radTree1.Nodes.Add(radTreeNode);
                }
                else
                {
                    parentNode.Nodes.Add(radTreeNode);
                }
                BindTree(list, radTreeNode);
            }
        }


public DataTable GetAllData4()
        {
            return GetDataTable(@"SELECT T1.*,T2.SECONDID,T2.SECONDNAME,T3.THIRDID,T3.THIRDNAME FROM T1 INNER JOIN T2 ON T1.MAINID=T2.MAINID
                                                LEFT OUTER JOIN T3 ON T2.SecondId=T3.SecondId ORDER BY T1.MAINID");
        }


public class ListItems
        {
            private int _mainId;
            private string _mainName;
            private int _secondId;
            private string _secondName;
            private int _thirdId;
            private string _thirdName;
            
            public int MainId
            {
                get { return _mainId; }
                set { _mainId=value ; }
            }
            public string MainName
            {
                get { return _mainName; }
                set { _mainName = value; }
            }
            public int SecondId
            {
                get { return _secondId; }
                set { _secondId = value; }
            }
            public string SecondName
            {
                get { return _secondName; }
                set { _secondName = value; }
            }
            public int ThirdId
            {
                get { return _thirdId; }
                set { _thirdId = value; }
            }
            public string ThirdName
            {
                get { return _thirdName; }
                set { _thirdName = value; }
            }

            public ListItems(int mainId,string mainName,int secondId,string secondName,int thirdId,string thirdName)
            {
                _mainId = mainId;
                _mainName = mainName;
                _secondId = secondId;
                _secondName = secondName;
                _thirdId = thirdId;
                _thirdName = thirdName;
            }
        }