Message Pump Mechanism - C / C++ / MFC Discussion Boards

newbie question
dialog based prog created file using CFile but cant write to it how do i write data from edit box to file
msvc+ 6.0 modal dialog prog

thanks to all for the help

get the data from the edit box into a cstring (using UpdateData(FALSE) or m_editbox.GetWindowText(...)) and then write the cstring to the file using CFile.Write(m_cstring)

Suspicious | :suss:

---
"every year we invent better idiot proof systems and every year they invent better idiots"

newbie question
dialog based prog created file using CFile but cant write to it how do i write data from edit box to file
msvc+ 6.0 modal dialog prog

thanks to all for the help

newbie with question
dialog based prog,i created a file using CFile now i want to write text and append how do i do this try and keep it as simple as possible
thanks to all who have helped me

Dear all,
If I have two window dialogs opening, say, A and B.
And if A is activating, I want that in A::OnOK(), it can call a function in B, say B::bfunction(). However, there is some CWnd function, e.g UpdateData(), SetForeGroundWindows(), SetWindowText() etc...included in the bfunction(), then it will fail in run time..

A::OnOK()
{
B dlg;
dlg.function();
}
Can I know how to solve it?

My target is, when A is activating, if the user press OK, then the B dialog will bring to top and A will call the B's function.....and then close A dialog.
Please help! Thanks a lot!!!

Rose | [Rose]

However, there is some CWnd function, e.g UpdateData(), SetForeGroundWindows(), SetWindowText() etc...included in the bfunction(), then it will fail in run time.

That's because the dialog isn't created until you call b.DoModal() or b.Create(). Just creating the C++ object doesn't create the dialog, so any functions that operate on the dialog via its HWND will fail.

--Mike--
http://home.inreach.com/mdunn/
I'm finger-lickin' good!

QUESTION on message pumping:

I have posted this a while back. But I hope to confirm my understanding is correct:

QUESTION 1:
What generates the BN_CLICKED message when a user click a mouse button over a button? Is the following description correct?

1. The user clicks a mouse button.

2. The mouse driver puts an item into the system input queue.

3. A system thread, which handles user input, retrieves this item and, using coordinates recorded by the driver, determines to which window this message
should be posted. Mouse messages are always sent to the window under the cursor (unless another window has captured mouse input).

Given the window handle the system detemines the thread to which this window belongs and posts WM_LBUTTONDOWN and WM_LBUTTONUP messages to the
message queue of this thread. Note, the message is posted to only one message queue since the system knowns to which thread the window belongs.

4. The application object, derived from CWinApp, will pickup the message from its thread message queue. Then route this message to the appropriate controls/windows.

5. Button window procedure receives WM_LBUTTONUP message and do the following:
(i) update the display of the button (depressed state and then the release state.)

//QUESTION: SendMessage( ) OR PostMessage( )??
(ii) sends WM_COMMAND/BN_CLICKED notification to "the parent window" or a "particular" control.
(iii) posts WM_COMMAND/BN_CLICKED notification to the application/thread message queue

6. Message map can be "expanded" to a subroutine that searches the message map upon reciept of a message/notification, then route the message to "appropriate" message handler in response a mapped message.
(This brings up the issue of message routing. ie. Things like searching the view class maps, then the document class, then the frame windows, then the app...)

QUESTION 2:
Quote from MSDN:

[OPEN QUOTE]
"This message is sent when the user selects a command item from a menu, when a control sends a notification message to its parent window, or when an accelerator keystroke is translated.

WM_COMMAND wNotifyCode = HIWORD(wParam); (EXAMPLE: BN_CLICKED??)
wID = LOWORD(wParam);
hwndCtl = (HWND) lParam; (WHY DO U NEED HANDLE WHEN CONTROL IDENTIFIER IS PROVIDED - wID ??)
"
[CLOSE QUOTE]

(1) When a button is clicked, is a WM_MESSAGE sent (or posts) to its parent window? or to its parent window's message queue? or to its parent's window procedure?
(2) Which parent? Immediate or top level in the hierachy?
(3) When a button is clicked, is a WM_MESSAGE (with BN_CLICKED as wParam) sent or is a BN_CLICKED messages sent?
(4) Does "notification" messages and "messages" refer to the same thing?

Thanks.

I guess the reason your message has gone unanswered is that its tough to answer - here's just a couple of thoughts...

First, there's a mix of win32 messaging architecture and MFC here - MFC has a way cool way of allowing you to map command messages to classes that you wouldn't ordiarily expect to get them (i.e. have no hwnd), and this mech is the stuff of DiLascia-like articles in itself, but I would think we should get the win32 stuff nailed down first.

Second, a recommendation - I've been struggling lately with a messaging problem that has me baffled - I picked up Jeffrey Richters book 'Advanced Windows' to check out his chapter on Windows Messaging and Asychronous Input - I think now I better read the whole book! You might want to check it out.

There's so much to look at here - just hard to do all at once. HTH

<<< In the name of GOD >>>
Hi all.
I want to set Check Sign inside text in menu.
My program is in dialog based mode.

void CTestglobalDlg::OnUpdateKhar(CCmdUI* pCmdUI)
{
pCmdUI->SetCheck(TRUE);
}

So, please say to me, how can i set dynamicaly check sign ...

Smile | :)

Hadi Rezaie

<<< In the name of GOD >>>

There is an article on Codeproject on doing this in a dialog app, I remember seeing it.

Christian

The content of this post is not necessarily the opinion of my yadda yadda yadda.

To understand recursion, we must first understand recursion.

<<< In the name of GOD >>>
Hi all.
I want to set Check Sign inside text in menu.
My program is in dialog based mode.

void CTestglobalDlg::OnUpdateKhar(CCmdUI* pCmdUI)
{
pCmdUI->SetCheck(TRUE);
}

So, please say to me, how can i set dynamicaly check sign ...

Smile | :)

Hadi Rezaie

<<< In the name of GOD >>>
Hi all.
I want to set Check Sign inside text in menu.
My program is in dialog based mode.

void CTestglobalDlg::OnUpdateKhar(CCmdUI* pCmdUI)
{
pCmdUI->SetCheck(TRUE);
}

So, please say to me, how can i set dynamicaly check sign ...

Smile | :)

Hadi Rezaie

i am writing an audio codec as part of a larger project. it involves playing etc of wave and mp3 files. i am using a class that simplifies the use of idirectsound for wave and xaudio.lib for the mp3s. in the test file (dialog based) i have written my class works fine but when added to a console application it won't play anything or it is not outputting sound
can anyone shed any light on this matter?
can dsound.lib be used in a console based app or only dialog based?
thanks
ruth

Hi,

I am trying to compile and link a workspace for a dll which has
only resource files. Before it used to complie and link..
I changed a a bitmap file by just replaing it with a new one
with the same name..
After that whenever i try to build, i get the following errors:
"CVTRES : fatal error CVT1106: cannot write to file"
"res32.res : fatal error LNK1123: failure during conversion to COFF: file invalid or corrupt"

I cleaned and tried to rebuild all, also tried restarting the machine.
Still the same error is being displayed.. can anybody suggest me to avoid
this error? The recent bitmap opens perfectly in mapaint or vc editor..

Regards,
Nayan Confused | :confused:

have you tried deleting the output directory completely (ie, debug or release) ?

Suspicious | :suss:

---
"every year we invent better idiot proof systems and every year they invent better idiots"

The linker seems to be invoking the coversion utility to convert an OMF object file to COFF format. This is default behavior. I found this note in the MSDN regarding ".Lib Files as Linker Input":

"LINK cannot link a library of 32-bit OMF objects created by the 16-bit version of LIB. To use an OMF library, you must first use the 16-bit LIB (not provided in Visual C++ for Windows NT) to extract the objects. You can then either link the OMF objects or use the 32-bit LIB to convert them to COFF and put them into a library. You can also use the EDITBIN.EXE tool to convert an OMF object to COFF. "

Not sure if this is the prob, but worth a look.

1) VC6 (no service packs applied I don't think - installed from MSDN January 2001 Enterpise CD's)

2) Windows 2000/SP1

3) Our app is an MFC MDI app with MFC is staticaly linked. I'm trying to embed a CPropertySheetEx in a dialog box. In Debug mode, it works fine, but in release it doesn't.

4) This code works on Windows 98 AND Windows NT 4 (SP5-6a) in both release and Debug modes.

5) It fails when I call the Create function in CPropertySheetEx, but since I'm in release mode, I can't trace into the code.

6) Do I have to install a VC6 service pack to fix this?

If anyone can provide any hints, tips, experiences or other helpful tidbits, I'd love to hear about it. Send mail here:

john.simmons@brooks.af.mil

Many thanks in advance.

hey john
i would strongly recommend applying service pack 4 at least (prolly 5 if you can get it) ... if the problem still persists it might be something more fundamental

---
"every year we invent better idiot proof systems and every year they invent better idiots"

Applied service pack 4 after leaving the original message. No change. We had to deliver a laptop (wint Win2K installed) with the application on it and were running through all the dialogs. This dialog crashed the app. Since we had to deliver the machine on Friday, and in anticipation of not getting an answer in team through this forum, we re-wrote the dialog to not use tabs (took about an hour).

I am still curious as to why this wouldn't work on Win2k, but works everywhere else.

Since there's a moderate amount of source code involved, maybe I could post this as an article and let everybody else have a stab at it too.

> but since I'm in release mode, I can't trace into the code.

Go to the project settings for the Release build. In the C++ (General Category) select Program Database for Debug Info. Next, in the Link tab (also General) check the Generate Debug Info box.

You may not be able to see things as well in the watch window, but at least you'll be able to see code and call stack. This is a great help for dealing with the effects of optimizations, uninitialized vars etc.

Thanks - I'll try that.

Well, I wrote a little test app that includes only the code necessary to build a dialog box with an embedded property sheet, and ran it on three windows 2000 systems. It worked on every one of them. This leads me to the conclusion that it's something else in the app that's crashing when the dialog box in question is being initialized.

"Good thing" - It wasn't my dialog box code that was causing the problem

"Bad thing" - I still don't know what the problem actually is yet.

Grrrr...

What is the difference between ADO and ADODB?
Thanks.