[perl-win32-gui-hackers] Creating a new Win32-GUI class

[Jeremy W. <jez...@ho...>]

Hi,

Brian Millham skin email on the users list has highlighted something that 
I've been thinking about for a while - how to make creating Win32-GUI 
classes easier/safer.

One of the problems creating a Win32-GUI class is were to store the instance 
data for the object while allowing the events to have access to this data.

In the current version of Win32-GUI you can stuff data into a structure and 
store it via the window with the UserData method, and then retrieve it in 
the event handler:

my $win=create the window
my $instancedata = create the instance data
#attach the instance data to the window
$win->UserData($instancedata);

in the event handlers:

#for window events
my $instancedata=$self->UserData();

#for child events, such as buttons on the window
my $instancedata=$self->GetParent->UserData();

This works well, but there is huge scope for clobbering the data if this 
approach was used for a formal class. Ok - in the class documentation you 
could mention that the instance data is stored as a hash, and if you need to 
store data via UserData you should use your own key - but I'm wondering if 
there is a better way to handle this? For example, we could add a "Data" 
method which could be used to store instance data, leaving the UserData 
method free for the user?

Thoughts?

Cheers,

jez.