On Thu, 3 Jun 2010 20:38:26 +0200 (CEST) Michael Van Canneyt <mich...@freepascal.org> wrote:
> > > On Thu, 3 Jun 2010, Graeme Geldenhuys wrote: > > > On 3 June 2010 17:24, Michael Van Canneyt <mich...@freepascal.org> wrote: > >> > >> You must override GetChildren. > >> > >> In the LCL, TWinControl overrides GetChildren to write child controls. > >> > >> It is documented. > > > > But why is GetChildren needed? Why can't TWriter use ComponentCount > > and Components[] like I have done in the TraverseComponents() > > recursive procedure? > > Because Borland decided otherwise. > > Actually, there is a good reason: some components create internal > components they own, and which they don't want to have streamed. > The 'GetChildren' allows you to control what gets streamed and > what not. For example a TOpenDialog is not in Controls, so it must be put into GetChildren. > > " Adds component to children list which have no parent. > > (TWinControl only lists components with parents) " > > > > > > Is that still true? In fpGUI I set Owner and Parent. What is > > different in fpGUI (compared to LCL or VCL) is that Owner = Parent, > > always. I don't see a need for them to be different - one widget can > > just as easily manage the lifespan of another widget. Re-parenting a > > widgets also works in fpGUI, by simply transferring the ownership to > > the new parent widget (inserting into Components[] array). > > In LCL the owner is always the form. Otherwise the form variables > would not work. Yes, and no. Think about Frames, Ancestors and special created components (e.g. TSynEdit creates some components owned by itself). Graeme, you might want to take a look at lazarus/designnonlcl/mywidgetset.pas Mattias _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
