wxperl-users

[wxperl-users] Validators

[Marcus <li...@wo...>]

I think the vaildators are a good idea. If I understand the concept
correctly, then this is how Perl/Tk works, only you have no choice.

The downside is that when you "bind" a variable to a control, then any
changes while you are working with the variable appear immediately in
the GUI. An example that caused me and my beta tester many many hours
of grief is the following. I had to escape backslashes when storing
paths in a config file, in the GUI they were unescaped. As you can
imagine unescaped backslashes can cause amazing problems when let
loose. The only workaround was to keep copying variables back and
forth, and making lots of temp variables.

Only a word of warning, which should be at the top of the docs, in form
of a "When to use..". Otherwise, I am in favour of the validators,
since they can be very useful.

Marcus

[wxperl-users] Validators

[Mark W. <ma...@ne...>]

Hi,

Please help, I am getting nowehere with these validators!!
- Does anyone have any more information on them or working source?
- Why was the PlValidator implemented instead of the Wx::Validator?
- How do I actually pass data To and From the window controls?
- Do I have to manually code the TransferDataToWindow for every panel in a
notebook or can I call InitDialog for the dialog containing the notebook
sizer? I tried this but no luck (nothing happened).

I have attached my simple version of a validator.

TIA
Mark Wardell

--------------------------------------------------------------------
package My::Validator;

use vars qw(@ISA); @ISA = qw( Wx::PlValidator );

sub new {
 my $class = shift;
 my $self  = $class->SUPER::new;
 $self->{data} = shift;
 return $self;
}

# see the docs for the three following functions
sub TransferFromWindow {
 my $self = shift;
 print "TransferFromWindow called\n";
 return 1;
}

sub TransferToWindow {
 my $self = shift;
 print "[TransferToWindow] data=${$self->{data}}\n";
 #print "TransferToWindow called\n";
 return ${$self->{data}};
}

sub OnChar {
 my $self = shift;
 print "[Validator] OnChar called\n";
 return 1;
}

sub Validate {
 my $self = shift;
 print "Validate called\n";
 return 1;
}

sub Clone {
 my $self = shift;
 #print "Clone called\n";

 # clone by creating a new object, which should, in the real class, have
copies of all
 # properties of $this

 # could/should we use something like Storable::dclone here??

 my $tmp = MOM::Validator->new($self->{data});
 return $tmp;
}

#---------------------------------------------------------------------------
---
1; # always return this

Re: [wxperl-users] Validators

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

On Thu, 20 Mar 2003, Mark Wardell wrote:

>Hi,
>
>Please help, I am getting nowehere with these validators!!
>- Does anyone have any more information on them or working source?
>- Why was the PlValidator implemented instead of the Wx::Validator?
  Implementation details. I caould explain in more detail, but I don't
think they are interesting for users.

>- How do I actually pass data To and From the window controls?
  It depends from the control... for a Wx::TextCtrl you use
GetValue/SetValue, for other controls, other methods.

>- Do I have to manually code the TransferDataToWindow for every panel in a
>notebook or can I call InitDialog for the dialog containing the notebook
>sizer? I tried this but no luck (nothing happened).

my $dlg = MyDialog->new( ... );
$dlg->SetExtraStyle( $dlg->GetExtraStyle | wxWS_EX_VALIDATE_RECURSIVELY );

This is off the top of my head, sorry if it is wrong.

>I have attached my simple version of a validator.
  It looks correct to me (but I haven't wxPerl to test it, here).

Regards
Mattia

Re: [wxperl-users] Validators

[James L. <jl...@bi...>]

Hi Marcus,
Validators are similar to, but not the same as, Perl/Tk.  As you say, in
Perl/Tk, changes to the underlying variable immediately appear in the Tk
widget - a great feature but also a source of problems, as you have found.

However, I think that Wx validators only transfer the data to the control
when $window->TransferDataToWindow is called, and back again when
$window->TransferDataFromWindow is called. (I'll check this out with some
trials).

For wxDialogs, these are both called automatically as part of Dialog
initialisation and dismissal (TransferDataFromWindow is only called when the
modal result is wxID_OK, I think).

Hence, using wxValidators we have an inbuilt mechanism whereby our variables
are only updated when the user OK's the window (and validation is
implemented, too!).

I ended up having to wrap my Tk widgets and windows in my own objects to
achieve this sort of functionality for a large (200 screens plus) system
I've been developing/supporting.  If only I'd known about wxWindows at the
time...  It's so much more consistent in its approach than Tk...

One feature I'm thinking of implementing is the ability to supply a callback
for the TransferToWindow and TransferFromWindow wxValidator methods, so that
we can supply data from object methods and pump data back into object
methods, rather than having to rely on variable addresses. (Most of my Perl
code is OO, and so I want to be able to use property accessors, rather than
property addresses).

Enough jabbering from me....

James


----- Original Message -----
From: "Marcus" <li...@wo...>
To: <wxp...@li...>
Sent: 05 July 2002 13:11
Subject: [wxperl-users] Validators


> I think the vaildators are a good idea. If I understand the concept
> correctly, then this is how Perl/Tk works, only you have no choice.
>
> The downside is that when you "bind" a variable to a control, then any
> changes while you are working with the variable appear immediately in
> the GUI. An example that caused me and my beta tester many many hours
> of grief is the following. I had to escape backslashes when storing
> paths in a config file, in the GUI they were unescaped. As you can
> imagine unescaped backslashes can cause amazing problems when let
> loose. The only workaround was to keep copying variables back and
> forth, and making lots of temp variables.
>
> Only a word of warning, which should be at the top of the docs, in form
> of a "When to use..". Otherwise, I am in favour of the validators,
> since they can be very useful.
>
> Marcus
>
>
>
>
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