在.net2003里，用vb程序想实现tree控件显示内容？

    class tree
    {
        public string id;
        public string nodetext;
        public string parentid;
    }

    class totreeview
    {
        arraylist datas;
        system.collections.hashtable treenodes;
        public void totree（system.windows.forms.treeview tv)
        {
            foreach（tree t in datas)
            {
                if（this.treenodes.containskey（t.parentid))
                {
                    system.windows.forms.treenode tn = （system.windows.forms.treenode)this.treenodes[t.parentid];
                    system.windows.forms.treenode addtn = new system.windows.forms.treenode（t.nodetext);
                    tn.nodes.add（addtn);
                    this.treenodes.add（t.id,addtn);
                }
            }
        }
    }