Subj:  WM_DEVMODECHANGE?                       Section: Visual Basic
From:  Wilson Smith             76702,1416     # 49017, 1 Reply 
  To:  All                                     Date: 10-Jul-92 12:31:14

How can my program tell if the default printer has changed?

I've been trying to intercept WM_DEVMODECHANGE messages (the way that
Jonathan Zuck's recent WinTech journal article intercepts WM_DROPFILES
messages), but haven't been having any luck.  Is there an easier way? 
What I'm trying to do is modify a menu of fonts when the available fonts
change...

Thanks.

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Subj:  WM_DEVMODECHANGE?                       Section: Visual Basic
From:  Wilson Smith             76702,1416     # 49216, * No Replies * 
  To:  Wilson Smith             76702,1416     Date: 11-Jul-92 14:21:13

Not sure if anybody's interested in this prob or not, but it looks like
WM_DEVMODECHANGE and WM_WININICHANGE messages don't go into the message
queue and therefore can't be examined with PeekMessage...  These messages
are apparently sent directly to VB which ignores them.

I wound up writing a tiny DLL in TP for Windows that installs a
window-procedure filter which monitors messages sent to the application. 
The DLL sets a flag if it sees any of the messages I'm interested in.  My
program is meanwhile checking this flag in a DoEvents loop. 

Seems like the long way around, but I couldn't figure any other way to do
it...

I'll upload the gory details in case anyone's curious or trying to tackle
a similar problem.  Filename FILTER.ZIP.

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MESSRECD.PAS  Turbo Pascal for Windows source code for a small DLL
              that installs a windows-procedure filter when it is
              loaded and sets a flag when a WM_DEVMODECHANGE or 
              WM_WININICHANGE message is intercepted.  The DLL contains
              a function which checks the value of this flag.
MESSRECD.DLL  Compiled DLL.

MESSRECD.MAK  Visual basic demo project showing usage of the DLL.
MESSRECD.FRM  Main form of the project.
MESSMAIN.BAS  The demo program's MAIN loop.