I finally got it to work based on your suggestions. The main problem is
that the types of wParam and lParam vary depending on the message,
whereas Win32::GUI::SendMessage assumes they are integers. By calling
SendMessage via Win32::API, you can tailor the call parameter types to
whatever the message specifies, including pointers to structures. Then,
you can "pack" the necessary structures. So, my previous example
becomes:
use constant LVM_SETITEMSTATE => 0x1000+43;
use constant LVIS_SELECTED => 0x0002;
my $sendMessage=new Win32::API("user32","SendMessage","NNIP","I");
die "Can't import SendMessage" unless defined $sendMessage;
my $lvItem=pack("IiiII",0,0,0,LVIS_SELECTED,LVIS_SELECTED);
$sendMessage->Call($mw->lvList->{-handle},LVM_SETITEMSTATE,-1,$lvItem);
That works, but to my dismay, it is no quicker than the loop I started
with! I'm not sure why, but the internal selection process is very slow.
The point is that the technique works, and opens a lot of other
possibilities.
A related bit of code programatically deselects a listview item (which I
don't believe is possible otherwise):
my $sendMessage=new Win32::API("user32","SendMessage","NNIP","I");
die "Can't import SendMessage" unless defined $sendMessage;
my $lvItem=pack("IiiII",0,0,0,0,LVIS_SELECTED);
$sendMessage->Call($mw->lvList->{-handle},LVM_SETITEMSTATE,$item,$lvItem
);
where the variable $item is the zero-based item to be deselected.
Thanks again, guys, for your help. Now I just need that notification
hook... :-)
Glenn
-----Original Message-----
From: Glenn Linderman [mailto:[EMAIL PROTECTED]
Sent: Tuesday, 06 January, 2004 12:46
To: Stephen Pick
Cc: [EMAIL PROTECTED]; perl-win32-gui-users@lists.sourceforge.net;
[EMAIL PROTECTED]
Subject: Re: [perl-win32-gui-users] New "Hook" Method
On approximately 1/6/2004 6:51 AM, came the following characters from
the keyboard of Stephen Pick:
> Hi,
>
> Arrrgh.
>
> The Win32 API deals, in the most part, with pointers to structs rather
> than structs themselves. You can't pass homemade structs as Perl
> references to SendMessage and hope that they're magically converted
into
> C pointers, that would indeed be nice, but it just isn't how it works.
pack/unpack does seem to have a conversion feature that deals with
pointers, though, which I have to admit I have never figured out how to
use it, or for certain why the feature is included. None of the
examples show its use.
I've idly wondered, from time to time, if one could obtain a pointer to
a homebuilt struct via pack, and then pass that as an integer value via
Win32::API to a parameter that expects a pointer, and if that would
work. Of course, Win32::API provides support for passing pointers to
plain structs, so I've never had to worry about that in reality. But
then since SendMessage doesn't, maybe it would be useful there?
I offer these comments and speculations not in the knowledge that this
is a workable solution, but that it might be close to one... please
don't laugh me off the list if it is completely ridiculous. But it
seems I always have something else more important to do when I get near
the computer, rather than try out this sort of thing.
Another alternative, of course, is to use the Win32::API module to
create a new interface to the Windows SendMessage API rather than using
the one in Win32::GUI.
> I recommend you take a look at the Win32::API module for Perl. This
may
> help you as it certainly helped me.
>
> Steve
>
>
>
>>-----Original Message-----
>>From: Glenn W Munroe [mailto:[EMAIL PROTECTED]
>>Sent: 06 January 2004 14:28
>>To: 'Stephen Pick'; perl-win32-gui-users@lists.sourceforge.net
>>Cc: [EMAIL PROTECTED]
>>Subject: RE: [perl-win32-gui-users] New "Hook" Method
>>
>>
>>
>>Thanks for that, Steve. I'll be looking out for the new
>>implementation.
>>In the meantime, I've been playing with some other messages and always
>>seem to hit the same problem with pointers to structures. When you say
>>"you can't use Perl to resolve the pointer" does that mean it is
>>impossible without XS code? Can you not just "pack" the correct
>>structure? For example, it would be nice to be able to select
>>all items
>>in a listview without going through a slooooow loop like:
>>
>>for (0..$mw->lvList->Count()-1) {$mw->lvList->Select($_)}
>>
>>Now,
>>
>>$mw->lvList->Select(-1)
>>
>>would be nice, but it doesn't work!
>>
>>Taking an idea from the VB world I tried this:
>>
>>use constant LVM_SETITEMSTATE => 0x1000 + 43;
>>use constant LVIF_STATE => 0x0008;
>>use constant LVIS_SELECTED => 0x0002;
>>
>>my
>>$lvItem=pack("IiiIIpiiii",LVIF_STATE,0,0,1,LVIS_SELECTED,"",0,0,0,0);
>>$mw->lvList->SendMessage(LVM_SETITEMSTATE, -1, \$lvItem);
>>
>>Needless to say, it fails miserably. I assume the problem is with the
>>pointer to the structure. Is the structure wrong or is the
>>problem with
>>the Perl variable reference? I know that a Perl variable is
>>represented
>>by a C structure internally; can you get a pointer to the actual data
>>value without resorting to XS code?
>>
>>Thanks again,
>>Glenn
>>
>>-----Original Message-----
>>From: Stephen Pick [mailto:[EMAIL PROTECTED]
>>Sent: Monday, 05 January, 2004 06:46
>>To: [EMAIL PROTECTED]; perl-win32-gui-users@lists.sourceforge.net
>>Cc: [EMAIL PROTECTED]
>>Subject: RE: [perl-win32-gui-users] New "Hook" Method
>>
>>Hi Glenn,
>>
>>
>>>I've been trying to get the ListView EditLabel feature to
>>
>>work. I can
>>
>>>turn it on OK and have got the handle to the edit control
>>
>>and through
>>
>>>that the control's contents. The problem is that the control is
>>
>>created
>>
>>>and destroyed automatically, and it is difficult to get
>>
>>access to the
>>
>>>final data. According to MSDN, an LVN_ENDLABELEDIT notification is
>>
>>sent
>>
>>>just before the control is destroyed, but I can't figure out how to
>>
>>get
>>
>>>to that. Would the new "Hook" method work? Again, according to MSDN,
>>
>>the
>>
>>>LVN_ENDLABELEDIT notification is sent in the form of a WM_NOTIFY
>>>message. Would I have to grab that? That sounds like it may
>>
>>be biting
>>
>>>off more than I can chew... Can you offer any pointers? Could you
>>>perhaps post a snippet of code showing how the "Hook" method works?
>>
>>You can't do this with Hooks at the moment. Personally I am not happy
>>with the current hook implementation as it does not satisfy what I
>>originally intended it to do. A new hook implementation should come in
>>the next few days, and I'll add the ability to hook notifications as
>>well as messages.
>>
>>The problem is that WM_NOTIFY messages are delivered with an
>>lParam that
>>is a pointer to a structure containing the notification code (like
>>LVN_ENDLABELEDIT). While you can use the current hooks
>>implementation to
>>catch WM_NOTIFY and see the wParam and lParam arguments, the lParam
>>pointer is useless to you in Perl and you can't use Perl to
>>resolve the
>>pointer and get the notification code from it.
>>
>>Watch this space...
>>
>>Steve
>>
>>
>>
>>
>
>
>
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--
Glenn -- http://nevcal.com/
===========================
The best part about procrastination is that you are never bored,
because you have all kinds of things that you should be doing.
