[fpc-pascal] WriteComponent not outputting a hierarchy of components?

[Michael Van Canneyt]

On Thu, 3 Jun 2010, Graeme Geldenhuys wrote:

> On 3 June 2010 17:24, Michael Van Canneyt <michael at 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.

> "  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.

Michael.