http://www.perlmonks.org?node_id=79672


in reply to Re: Re: "Always on top" with Win32 and Tk
in thread "Always on top" with Win32 and Tk

I've got it working now! As before I've removed most of the code from my program.

use Tk; use Win32::API; ... # Windows constants my ($OnTop, $NoTop, $Top) = (-1, -2, 0); my ($SWP_NOMOVE, $SWP_NOSIZE) = (2, 1); # 'always on top' state my $isOnTop = $NoTop; ... # Create a Win32::API object for SetWindowPos my $SetWindowPos = new Win32::API("user32", "SetWindowPos", [N,N,N,N,N +,N,N], N); # and one for FindWindow my $FindWindow = new Win32::API("user32", "FindWindow", [P,P], N); ... my $w = new MainWindow; ... my $aotCBut = $w->Checkbutton(-text => "Always on top", -onvalue => $OnTop, -offvalue => $NoTop, -variable => \$isOnTop, -command => sub { # get a handle to the toplevel window containing our Perl/Tk a +pp my $class = "TkTopLevel"; my $name = $w->title; my $NULL = 0; my $topHwnd = $FindWindow->Call($class, $name); if ($topHwnd != $NULL) { # change 'always on top' state $SetWindowPos->Call($topHwnd, $isOnTop, 0, 0, 0, 0, $SWP_N +OMOVE | $SWP_NOSIZE); }; }) ->pack(-side => "bottom", expand => "yes", -fill => "x"); ... # start the UI MainLoop;

The Win32 FindWindow API call will return a handle to a window with the specified title and class. Perl/Tk creates windows of the class TkTopLevel. You must call this after the window has been mapped (i.e. after MainLoop), otherwise you won't get a valid window handle.

A useful reference when using Win32::API is here, it talks about Visual Basic but you can fairly easily convert it to Perl.

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Kevin O'Rourke