//刷新一下复合框，同时清除分类输入框
procedure TmainForm.RefreshClass;
begin
  comboBox1.Items.Clear;
  edit3.Text:='';
  qr.Close;
  qr.SQL.Clear;
  qr.SQL.Add('select cls_name from tb_article_class');
  qr.Open;
  if not qr.Eof then
  begin
    qr.First;
    while not qr.Eof do
    begin
      combobox1.Items.Add(qr.FieldByName('cls_name').AsString);
      qr.Next; 
    end;
  end;
  //qr.Close;
end;