TabControl und Events

[TiGü]

Zu 1. aus der Unit ComCtrls:

Delphi-Quellcode:

...
procedure CNNotify(var Message: TWMNotify); message CN_NOTIFY; // <--- CN_ anstatt WM_
...

Delphi-Quellcode:

procedure TCustomTabControl.CNNotify(var Message: TWMNotify);
begin
  with Message do
    case NMHdr.code of
      TCN_SELCHANGE:
        Change;
      TCN_SELCHANGING:
        begin
          Result := 1;
          if CanChange then Result := 0;
        end;
    end;
end;

Change wird in der abgeleiteten Klasse TPageControl aufgerufen:

Delphi-Quellcode:

procedure TPageControl.Change;
var
  Form: TCustomForm;
begin
  if TabIndex >= 0 then
    UpdateActivePage;
  if csDesigning in ComponentState then
  begin
    Form := GetParentForm(Self);
    if (Form <> nil) and (Form.Designer <> nil) then
      Form.Designer.Modified;
  end;
  inherited Change;
end;