schleife will einfach nicht.

[DeddyH]

Ich würde das eher so machen:

Delphi-Quellcode:

type
  TPingForm = class(TForm)
    ...
    private
      IsPing: Boolean;
    ...
  end;

procedure TPingForm.PingTimerTimer(Sender: TObject);
const sPing: array[Boolean] of String = ('Pong','Ping');
begin
  IsPing := not IsPing;
  Label1.Caption := sPing[IsPing];
end;