Re: [wxperl-users] how can i access a control from within another package

[Mattia B. <mb...@ds...>]

On Fri, 26 Oct 2001, Paul Schabl wrote:

>Hi,
> 
>i'm just starting using wxPerl and have the following problem: 
>in the code below, in the package myFrame, i have a tree and a
>textcontrol and want to print 
>some data into the textcontrol each time an item in the treecontrol is
>selected (e.g. directory-listing);
>how can i access the textcontrol from within the sub OnSelChange in
>package myTreeCtrl ?
>myFrame->TextCtrl->AppendText() doesn't work.
This is because you do not have a 'TextCtrl' method in the
myFrame class; second even if you had it, you need to call it
on an instance of the class .

in the OnSelCHange method add:
  my $frame = $this->GetParent();
  my $textctrl = $this->{TEXTCTRL}; # see below
  $textctrl->AppendText( 'Hi!' );
  # of course you could do
  # $this->GetParent->{TEXTCTRL}->AppendText( 'Hi!' );

in addition you can add a TextCtrl method to myFrame, like this

sub TextCtrl { $_[0]->{TEXTCTRL} }

and use $frame->TextCtrl instead of $frame->{TEXTCTRL}

if you feel that this makes your code cleaner.

Yet another solution is to pass the TextCtrl to the myTreeCtrl
constructor

i.e.

package myTreeCtrl;

# ...

sub new {
   my $class = shift;
   my $textctrl = shift;
   my $this = $class->SUPER::new( @_ );

   $this->{TEXTCTRL} = $textctrl;

}

and use it as myTreeCtrl->new( $textctrl, @other_parameters );

this avoids depending on the fact that the textctrl and the treectrl are
childs of the frame ( you might subsequntly change the layout and
have to change all calls to ->GetParent() to something else.
 
Regards
Mattia