[fpc-devel] Streaming readonly properties

[Vincent Snijders]

Michael Van Canneyt schreef:
> 
> 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 ?

I am not sure I understand your question.

EditLabel is a published property of TLabeledEdit.

> 
>> 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...

I will try.

Vincent