Re: [wxperl-users] Fwd:[wxperl-commits] XRC and Subclassing

[John R. <jr...@ce...>]

On Jul 5, 2006, at 12:25 AM, Mattia Barbon wrote:

> [Forwarding to the correct list]
>
> Hello,
>
> I am trying to subclass controls created using XRC but I am having
> difficulty with the initialisation.
>
> The problem is that the controls are created with the 2-step  
> process using
> the default contructor when subclassed by the XRC loading mechanism.
>
> For example,
>
> Wx::SomeCtrl->new;		# without parameters
> Wx::SomeCtrl::Create( @_ );	# all parameters specified here
>
> Unfortunately the Create() method is not virtual (is that the correct
> terminology?) or I cannot override this method, so I am unable to  
> "assist"
> woth the control creation, and provide additional initialisation  
> parameters
>
> Is this possible in plain Perl or do I need to go deeper to the XS  
> level?
>
> Many thanks
> Mark

I hope Mark is actually reading this list...

Yes, it appears that it isn't possible to override Create nor to pass  
it arguments. The way I work around that is to write an init function  
for my subclasses which I call explicitly after loading a resource  
which uses them. It's neither elegant nor convenient, but it can be  
done in Perl.

I think that the way to fire off the subclass's create (as well as to  
parse and pass additional parameters from the resource file) is to  
write a custom XmlResourceHandler, but I have not tried this myself.

Regards,
John Ralls