编写自动生成treeview的程序，编译时出现这问题，身为初学者琢磨了很久都没搞懂为什么。哪位路过的帮我看看哈！谢了！
unit Unit4;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, ComCtrls;

type
  TForm4 = class(TForm)

    Query1: TADOQuery;
    TreeView1: TTreeView;
    ADOConnection1: TADOConnection;

    procedure FormShow(Sender: TObject);
    procedure TreeView1Change(Sender: TObject; Node: TTreeNode);

  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form4: TForm4;

implementation

{$R *.dfm}
type
  Ttable= array[1..2000,1..2] of string;
  Tindextable= array[1..2000,1..1] of integer;
var
  pnode:TTreenode;
  temptable:Ttable;
  indextable:Tindextable
  pnum:integer;
  snum:integer;
  itemlevel:integer;
  sname:string;
procedure TForm4.FormShow(Sender: TObject);
begin
    treeview1change(nil,nil);
end;
procedure TForm4.TreeView1Change(Sender: TObject; Node: TTreeNode);
begin
     if treeview1.items.count<>0 then
     begin
        treeview1.items.Item[0].Delete ;
     end;
     query1.close;
     query1.Open;
     while not query1.Eof do
     begin
          pnum:=query1.fieldbyname('父编号').asinteger;
          snum:=query1.fieldbyname('编号').asinteger;
          sname:=query1.fieldbyname('名次').asstring;
          itemlevel:=query1.fieldbyname('层次').asinteger;
          temptable[snum,2]:=query1.fieldbyname('最大子号').asstring;
          if (itemlevel=0) then
          begin
           pnode:=treeview1.Items.addfirst(nil,sname);
           indextable[pnode.AbsoluteIndex+1,1]:=snum;
           temptable[snum,1]:=inttostr(pnode.absoluteindex);
           end
           else
           begin
              pnode:=treeview1.items.item[strtoint(temptable[pnum,1])];
              pnode:=treeview1.Items.AddChild(pnode,sname);
              indextable[pnode.AbsoluteIndex+1,1]:=snum;
              temptable[snum,1]:=inttostr(pnode.AbsoluteIndex );
           end;
              query1.next;
           end;
end;



end.

我是学机械的，可毕设做的却是产品数据管理系统，现在卡在了如何自动生成treeview上了，，，求指教。