[fpc-devel] Streaming readonly properties

[Michael Van Canneyt]

On Wed, 13 Dec 2006, Vincent Snijders wrote:

> Michael Van Canneyt schreef:
> > 
> > On Wed, 13 Dec 2006, Vincent Snijders wrote:
> > 
> > > Michael Van Canneyt schreef:
> > > > On Tue, 12 Dec 2006, vsnijders at quicknet.nl wrote:
> > > >
> > > > > As said in an earlier mail I have problems streaming the property
> > > > > EditLabel: TBoundLabel read FEditLabel;
> > > > > of a TLabeledEdit with fpc 2.1.1.
> > > > >
> > > > > Some discussion on #fpc led to the conclusion that streaming a
> > > > > readonly
> > > > > persistant should be allowed, because you write to the properties of
> > > > > the
> > > > > readonly persistant property.
> > > > >
> > > > > Attached is a proposal to fix it.
> > > > Delphi does not stream readonly properties. So we won't either.
> > > >
> > > > The proper solution for this is support for csSubComponent in
> > > > TComponent.
> > > Can you elaborate a bit, what you mean by that? What should be changed and
> > > where?
> > 
> > Delphi has a ComponentState csSubComponent. This flag should be set
> > if you publish a property of type TComponent, and the TComponent instance
> > is 'owned' by the object that publishes it, i.e. it's NOT a reference to an
> > other existing TComponent.
> > 
> > The owned TComponent has 'csSubComponent' in it's componentstyle. This tells
> > delphi to stream the component's properties as part of it's owning
> > component, and not just a reference to it.
> > 
> > The IDE will need support for this, as well TComponent and the streaming
> > system. (The latter part is probably the easy part ;) )
> 
> So far so good.
> 
> The IDE supports this (no drop downbox in the IO, but you can expand to set
> the owned component's properties). The owned component has the csSubComponent
> in its component style:
> 
>   Include(FEditLabel.ComponentStyle, csSubComponent);
>   Include(FEditLabel.ControlStyle, csNoDesignSelectable);
> 
> So where should the streaming occur?

When EditLabel is encountered ?

> 
> Should I amend to patch to allow streaming properties of readonly
> subcomponents?

Yes, please do. It should be quite like the check you made before...

Michael.