[Lazarus] Help to find cause of crash in IDE after revision 19044

Luiz Americo Pereira Camara luizmed at oi.com.br
Sun Mar 22 14:48:58 CET 2009


Alexander Klenin escreveu:
> On Sun, Mar 22, 2009 at 22:03, Luiz Americo Pereira Camara
> <luizmed at oi.com.br> wrote:
>
> Ok, I have installed VTV (by the way, it needs not only LCLExtensions,
> but MultiLog package).
>   

Oh yeah, sorry. When i do a release i'll remove that dependency.

> I can reproduce the issue, but this time I am inclined to say this is
> VTV bug, since
> similar properties, like StringGrid.Columns and SdfDataSet.FieldDefs work fine.
>   

The difference to that properties is that in VTV case Columns is a 
subproperty (child of Header).

> Also, if I disable IsIntresting function, the IDE stops crashing, I
> can still see anomalies
> with Columns property -- for example, TreeView part of object inspector displays
> garbage after invoking Columns editor for VTV component.
>   
The problem is that worked fine from 2 years until revision 19044. 
Anyway i could not find any different approach in VTV since i already 
removed the existent hack. Can you point any?

I've found where the crash occurs. See other mail.
>   
>> The problem is that Columns is a property of Header
>> (TVirtualStringTree.Header.Columns).
>>
>> Previously Columns where streamed as a direct child of
>> TVirtualStringTree using DefineProperties method as a workaround to
>> Delphi bug. I removed this hack and now Columns is streamed as child of
>> Header.
>> Is there any method, other than DefineProperty, that can change a
>> property hierarchy?
>>
>> FYI Columns.GetOwner returns the Header instance.
>>     
>
> Streaming child properties correctly is, unfortunately,
> undocumented and clumsy process.
> See e.g. r18774 for a sample of changes required (note overrides for
> TBasicChartSeries class).
> If you will use that code, take into account a possible differences in
> requirement -- TChart
> displays its series as child nodes in Object Inspector's treeview.
> You might or might not want this for VisualTreeView columns.
>   

I'll stick with the basics and hope that the bug can be fixed.

Luiz






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