procedure TForm1.Button1Click(Sender: TObject);
begin
   Panel1.EnumControls(
      function (Control: TControl): TEnumControlsResult
      begin
         if not Control.Visible then
            Result := TEnumControlsResult.Discard
         else
         begin
            ShowMessage(Control.Name + ' [' + Control.ClassName + ']');
            Result := TEnumControlsResult.Continue;
         end;
      end);
end;