Hi monks, happy new year.

I'm not quite sure how to get Win32::GUI to display the familiar sort arrows in ListView headers. As this feature is not exposed by Win32::GUI, a suitable HDITEM structure has to be sent as the contents of the HDM_SETITEM message.

Which I translate into:

sub HDI_FORMAT   {0x4}
sub HDF_SORTDOWN {0x400} 
sub HDF_STRING   {0x4000}
sub HDM_SETITEM  {0x1200 + 4}

$hditem = pack("LLLLLLLLLLL",      
               HDI_FORMAT,                # mask 
               0,                         # cxy
               0,                         # pszText
               0,                         # hbm
               0,                         # cchTextMax
               HDF_SORTDOWN | HDF_STRING, # fmt
               0,                         # lParam
               0,                         # iImage
               0,                         # iOrder
               0,                         # type
               0                          # pvFilter
              );

$hditem_ptr = pack('P44', $hditem);
$hwnd = $myListView->GetHeader();
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None of the following calls seem to do anything, their return value being "4":

Win32::GUI::SendMessage($hwnd, HDM_SETITEM, $columnClicked, $hditem_pt
+r);
Win32::GUI::SendMessage($hwnd, HDM_SETITEM, $columnClicked, unpack('L!
+', $hditem_ptr));

$sendMessage = new Win32::API("user32","SendMessage","NNIP","I");
$sendMessage->Call($hwnd, HDM_SETITEM, $columnClicked, $hditem_ptr);
$sendMessage->Call($hwnd, HDM_SETITEM, $columnClicked, unpack('L!', $h
+ditem_ptr));

$listview->Show(1); # refresh
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However, Win32::GuiTest gets the job done:

use Win32::GuiTest qw( :ALL );

$hditem_ptr = AllocateVirtualBuffer($hwnd, 44);
WriteToVirtualBuffer($hditem_ptr, $hditem);
SendMessage($hwnd, HDM_SETITEM, $columnClicked, $hditem_ptr->{ptr});
FreeVirtualBuffer($hditem_ptr);
ShowWindow($hwnd, 1); # refresh
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What am I missing here? Is it an address space issue or am I pack'ing the SendMessage lParam incorrectly? I'd really like to use Win32::GUI's SendMessage.

Update

The problem are these declarations:

sub HDM_FIRST    {0x1200}
sub HDM_GETITEM  {HDM_FIRST+11}   # !WRONG: HDM_FIRST not a function c
+all, result is 1211
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Here's the fix.

sub HDM_GETITEM  {&HDM_FIRST+11}  # RIGHT: HDM_FIRST called, result is
+ 4619
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So, for posterity, here's the complete code to display sort arrows in Win32::GUI::ListView headers (you should put this on a ColumnClick event handler on the ListView):

sub HDI_WIDTH    {0x1}
sub HDI_FORMAT   {0x4}
sub HDF_SORTUP   {0x400}
sub HDF_SORTDOWN {0x200}
sub HDM_FIRST    {0x1200}
sub HDM_GETITEM  {&HDM_FIRST+11}
sub HDM_SETITEM  {&HDM_FIRST+12}

sub HDF_LEFT     {0x0}
sub HDF_RIGHT    {0x1}
sub HDF_CENTER   {0x2}
sub HDF_STRING   {0x4000}


 # loop over columns, setting the arrow on the clicked column
 # and removing it from the others

for (0 .. scalar $myListView->GetColumnOrderArray()){
  my $arrowstate = ($_ == $columnclicked) # $columnclicked courtesy of
+ ColumnClick event handler
                   ? $state               # $state can be 'asc' or 'de
+sc' (or something alike)
                   : 'unset';             #        and 'unset'

  setSortArrow($myListView, $_, $arrowstate);
}




sub setSortArrow {

  my ($listview, $column, $state) = @_;

  # request information on the format and the width of the column head
+er
  my $hditem = pack("L11", 
                    HDI_FORMAT | HDI_WIDTH,    # mask
                    0,                         # cxy
                    0,                         # pszText
                    0,                         # hbm
                    0,                         # cchTextMax
                    0,                         # fmt
                    0,                         # lParam
                    0,                         # iImage
                    0,                         # iOrder
                    0,                         # type
                    0                          # pvFilter
                   );

  my $ptr = pack('P44', $hditem);

  my $hwnd = $listview->GetHeader();
  my $r = Win32::GUI::SendMessage($hwnd, HDM_GETITEM, $column, unpack(
+'L!', $ptr));

  return unless $r;

  my @members = unpack('L11', $hditem);  # cxy and fmt now updated by 
+call to HDM_GETITEM

  my $width = $members[1];
  my $cxy   = 0;
  my $fmt   = sprintf("%X", $members[5]);
  my $justf = (($fmt | HDF_RIGHT) eq $fmt) ? HDF_RIGHT 
                                           : ((($fmt | HDF_CENTER) eq 
+$fmt) ? HDF_CENTER
                                                                      
+      : HDF_LEFT);
  my $flags = HDF_STRING | $justf;    # keep text and its justificatio
+n

  unless($state eq 'unset'){
    $flags |= ($state eq 'asc') ? HDF_SORTUP : HDF_SORTDOWN;

    # text on narrow columns will be trunacted with ellipses: adjust w
+idth a little
    # FIXME: "80" is a little arbitrary and repeated sorting will keep
+ very narrow 
    #        columns growing until they are 80 pixels wide

    if((($fmt & HDF_SORTDOWN & HDF_SORTUP) > 0) && ($width < 80)){
      $cxy = $width + 5;
    }
  }

  $members[0] = HDI_FORMAT | ($cxy ? HDI_WIDTH : 0x0);
  $members[1] = $cxy;
  $members[5] = $flags;

  $hditem = pack("L11", @members);
  $ptr = pack('P44', $hditem);

  $r = Win32::GUI::SendMessage($hwnd, HDM_SETITEM, $column, unpack('L!
+', $ptr));

}

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Comments and improvements are welcome.