Re: MFC and User Defined objects

From:
"AliR \(VC++ MVP\)" <AliR@online.nospam>
Newsgroups:
microsoft.public.vc.mfc
Date:
Tue, 13 Mar 2007 19:34:31 GMT
Message-ID:
<b1DJh.3013$Qw.2264@newssvr29.news.prodigy.net>
"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp> wrote in message
news:ON$ubCaZHHA.4692@TK2MSFTNGP04.phx.gbl...

one-trick-pony wrote:

Greetings,

I am trying to PostMessage from a user defined generic class/object in
MFC Dialog based application to Dialog/main window. I don't know how
to do that. I am utilizing worker threads. A thread instantiates an
object(from user defined generic class) and utilizes newly created
object. What user defined object code does is actually launch a
process, for sake for argument lets say, Windows Notepad.exe using
CreateProcess. As long as that process is running, I want to
PostMessage that updates a progress bar on Main GUI dialog. I can do
it if I embed the code right into my application by writing the code
directly into it or declare, define and use member function of Dialog/
main program itself. But I want to learn new material by incorporting
a user defined class and then interacting with main application code.
To recap:

MFC Dialog based Main application exectues-> It launches a thread. ->
Thread uses user defined generic class to instantiate a new object. -

New Object should run and should PostMessage to Main window to


update progress bar.

Again, I don't know how to do this. How to tell newly created object
from user defined class, which is running within a Worker Thread, to
successfully post message to main GUI? I know that Worker threads are
not allowed to interact with GUI objects.

Any good software engineering solution will be greatly appreciated. I
thank you.


Your object in a worker thread needs to be passed a CWnd* or HWND for the
main window. This can be passed into to the thread function via the
thread parameter.

Then you can use pwnd->PostMessage or ::PostMessage(hwnd,..) from your
object. Example here...
http://vcfaq.mvps.org/mfc/12.htm

--
Scott McPhillips [VC++ MVP]


I would pass the HWND instead of the CWnd, you never know CWnd my not be
thread safe. Or the CWnd object might get destroyed without the thread
knowing about it.

AliR.

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