Überwachen von Objekteigenschaften

[DeddyH]

Was mir jetzt spontan einfällt: die Message CM_ENABLEDCHANGED abzufangen.

Delphi-Quellcode:

type
  TButton = class(StdCtrls.TButton)
  private
    FOnEnabledChanged: TNotifyEvent;
    procedure CMEnabledChanged(var Message: TMessage); message CM_ENABLEDCHANGED;
  public
    property OnEnabledChanged: TNotifyEvent read FOnEnabledChanged write FOnEnabledChanged;
  end;

  TFormTest = class(TForm)
  ...
  private
    { Private-Deklarationen }
    procedure DoOnChange(Sender: TObject);
  ...   


procedure TButton.CMEnabledChanged(var Message: TMessage);
begin
  inherited;
  if Assigned(FOnEnabledChanged) then
    FOnEnabledChanged(Self);
end;

procedure TFormTest.DoOnChange(Sender: TObject);
begin
  if Sender is TButton then
    ShowMessage(TButton(Sender).Name + ' hat sich geändert');
end;

procedure TFormTest.FormCreate(Sender: TObject);
begin
  Button1.OnEnabledChanged := DoOnChange;
end;