[fpc-pascal] Lazarus

[Mattias Gaertner]

On Fri, 17 Mar 2006 01:34:11 -0300
"Felipe Monteiro de Carvalho" <felipemonteiro.carvalho at gmail.com> wrote:

> On 3/17/06, Gökhan Ersumer <sky_khan at yahoo.com> wrote:
> > Yep, I said so (on last paragraph) but IMO this is
> > bad for maintanence and/or component writers.
> 
> I wrote TTrayIcon component to implement multiplatform system tray and
> also did a lot of things on the Qt interface for Lazarus, and also
> started the Windows CE interface, and I had no idea about that vtm
> thing until I read your e-mail.
> 
> So I can conclude that one can write components and even new
> interfaces (and maintain them) without ever knowing about this.

That's exactly the idea of creating a vmt, instead of working with a fake:
No extra code or headaches for the components, property editors, component
editors, object inspector, ... .

The vmt is created only for the lookuproot (TForms/TDataModules). For
example a TForm1. This is a class of its own, so it needs a vmt of its own.
This way the class can be renamed and the classtype pointer can be used
normally. A TTrayIcon put onto the form/datamodule does not get an extra
vmt. When the IDE supports designing components, and you want to design a
TTrayIcon descendent, then the IDE will create a TTrayIcon1 vmt.

See designer/jitforms.pp function CreateNewJITClass.


Mattias