delphi DBTreeview与数据库连接的数据存取

//操作：
procedure TForm1.act_GetListExecute(Sender: TObject);
begin
   FieldList := TStringList.create;
   TreeView1.items.BeginUpdate; 
   Table1.Close;   // 关键！这样才能在插入、更新、删除表数据后实现实时更新
   Table1.Open;    // 关键！
   Table1.first;
   while not Table1.eof do
     begin
        TreeAddItem(TreeView1, GetFieldList, Table1.getBookmark, false); 
        Table1.next;
     end;
   FieldList.clear;
 
   TreeView1.Alphasort;
   TreeView1.items.Endupdate;
   TreeView1.Refresh;
   TreeView1.FullExpand;     // 全部展开
end;
 
//GetFieldList函数：
function TForm1.GetFieldList: TStringList;
begin
     FieldList.clear;
     FieldList.add(Table1.fieldbyname('Level1').AsString);
     FieldList.add(Table1.fieldbyname('Level2').AsString);
     FieldList.add(Table1.fieldbyname('Level3').Asstring);
     Result := FieldList;
end;