[lazarus] Win32 menu does not work

[Mattias Gaertner]

On Tue, 24 Jun 2003 11:12:07 +0200 (W. Europe Daylight Time)
Michael Van Canneyt <michael.vancanneyt at wisa.be> wrote:

> 
> 
> On Tue, 24 Jun 2003, Mattias Gaertner wrote:
> 
> > On Tue, 24 Jun 2003 10:19:29 +0200
> > "Micha Nelissen" <mdvpost at hotmail.com> wrote:
> >
> > > Hi.
> > >
> > > > After some debugging I found out that MENUINFO.WID is a 32 bit
> > > > integer, but it contains a 16 bit application defined value. It
> > > > seems the application is responsible for providing an increasing set
> > > > of numbers in this identifier. Currently (see win32object.inc:2610)
> > > > it is assigned a pointer which is a 32 bit value and thus too wide.
> > > > It could be that the upper 16 bits are used for the
> > > > WM_COMMAND.wNotifyCode but I am not sure.
> > >
> > > I have confirmed my above statements. The attached (very ugly) patch
> > > shows how to make the menus work. It basically cuts off the high part
> > > of the pointer, forcing it to be a 16 bit value as windows expects.
> > > Ideally, one would keep a counter of some sort to keep track of used
> > > menu item ids(also known as commands).
> > >
> > > The patch attached proves that using 16 bit integers, the menus will
> > > work. Apply it in the lazarus/lcl/interfaces/win32 directory.
> >
> > Thanks. Applied.
> >
> >
> > > I would like to hear your comments in the patch (probably not correct
> > > coding style), it's a bit ugly (using pointers for the item ids), but
> > > the current code is just wrong (with respect to the menu item ids).
> >
> > I can't test it, so I can't say much. Can you create a short list which
> > example and/or component does/does not work and what needs to be done?
> > Just start it, it does not need to be complete. Maybe this will help
> > other win32 devels.
> 
> As for the above patch: there should be the possibility to store the
> command ID in the menu item records, and the application should keep
> track of these commands. In Delphi, it is done using the TBits class:
> 
> var
>   CommandPool: TBits;
> 
> function UniqueCommand: Word;
> begin
>   Result := CommandPool.OpenBit;
>   CommandPool[Result] := True;
> end;
> 
> and in TMenuItem.Create:
> 
> ...
>   FCommand := UniqueCommand;
> ..
> 
> When the menu item is destroyed, the bit is freed again:
> 
>   if FCommand <> 0 then
>     CommandPool[FCommand] := False;
> 
> Just clipping the lower 16 bits may work most of the time,
> but does not guarantee a unique ID.

Right.
Although the ID should be stored somewhere in the win32 interface, since
they are win32 specific.


Mattias