C / C++ / MFC

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

8-May-08 21:12

the following is my code,give me some advise.
sometimes the dialog can close by this,sometimes doesnot work like i want.

LRESULT CSettingDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{

switch(message)
{

case WM_COMMAND:

//I use the button to exit the dialog,which is static create by me!
if(wID==IDC_Btn_SetEsc) //static create the button
{
this->SendMessage(WM_CLOSE,NULL,NULL);
return TRUE;

//break;
}

case WM_CLOSE:
// case WM_DESTROY://2008--4--24 xqh_xg
DeleteObjects(); //free the used object
break;

}//switch(message)

return CDialog::WindowProc(message, wParam, lParam);
}

Mark Salsbery9-May-08 6:51

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

9-May-08 6:51

Why, oh WHY are you using a WindowProc() override in an MFC dialog?

Or is this not MFC? Suspicious | :suss:

MFC modal dialogs are closed with CDialog::EndDialog().
MFC modeless dialogs are closed with CWnd::DestroyWindow().

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

xqhrs23210-May-08 16:12

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message. [modified]

10-May-08 16:12

Because the button which is used to close the Diaolg is created by myself.
I donot use the ok button and cancel button which are displayed on the Dialog by default.I want to close the Dialog by just send WM_CLOSE message.AS we all know ,when we send the WM_CLOSE message, the WM_Destory and WM_QUIT message will occur following.so i think i can close the Dialog by just send WM_CLOSE.But the idea sometimes work well ,sometimes it doesnot.
I donot know what is the wrong.

Mark Salsbery10-May-08 17:07

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

10-May-08 17:07

xqhrs232 wrote:
Because the button which is used to close the Diaolg is created by myself.

There's rarely a need to override WindowProc(). If you're using MFC,
why not just use MFC's message handling instead of doing it the Win32 way?

Regardless, your code snip is incomplete so it's not much help.

The WM_CLOSE message should be posted, not sent from your window proc.

BEGIN_MESSAGE_MAP(CSettingDlg, CDialog)
	ON_BN_CLICKED(IDC_Btn_SetEsc, &CSettingDlg::OnBnClickedBtn_SetEsc)
	ON_WM_CLOSE()
END_MESSAGE_MAP()


LRESULT CSettingDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
//	switch(message)
//	{
//		case WM_COMMAND:
//
//			//I use the button to exit the dialog,which is static create by me!
//			if(wID==IDC_Btn_SetEsc) //static create the button
//			{
//				this->SendMessage(WM_CLOSE,NULL,NULL);
//				return TRUE;
//		
//				//break;
//			}
//
//		case WM_CLOSE:
//			// case WM_DESTROY://2008--4--24 xqh_xg
//			DeleteObjects(); //free the used object
//			break;
//
//	}//switch(message)

	return CDialog::WindowProc(message, wParam, lParam);
} 


void CSettingDlg::OnBnClickedBtn_SetEsc()
{
	PostMessage(WM_CLOSE);
}

void CSettingDlg::OnClose()
{
	DeleteObjects(); //free the used object

	CDialog::OnClose();
}

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

modified on Saturday, May 10, 2008 11:18 PM

xqhrs23213-May-08 3:28

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

13-May-08 3:28

if the button which i used to exit the dialog is created by dynamic.what can i do?if this, i must use windproc function which can capture the WM_COMMAND which is sended by common control.

Mark Salsbery13-May-08 4:45

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

13-May-08 4:45

You can do it the same way I showed since you know the ID of the
button (IDC_Btn_SetEsc) at compile time Smile | :)

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

xqhrs23213-May-08 20:38

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

13-May-08 20:38

if i want to use the WM_COMMAND message to dispose the common control's press message.what can i do?i think my idea is good,but something is wrong which i donot know now!Because the MFC message is a way,the win32 Messge is another way.i think that my way which uses the Winproc( ) function(in WIN32 message way)is good way.may be i make a mistake in some another positon which i donot know now!
you think that my win32 message way is wrong?that in MFC Appication we cannot use the win32 message way(Winproc( ) function).

Mark Salsbery14-May-08 5:53

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

14-May-08 5:53

xqhrs232 wrote:
Because the MFC message is a way,the win32 Messge is another way

What do you mean? They are all Windows messages - there's no MFC messages.

xqhrs232 wrote:
you think that my win32 message way is wrong?

Not wrong, just unnecessary. You're using MFC - why use a Win32 style Window proc
when MFC handles that for you? If you do that, then all MFC is, is an expensive wrapper
around an HWND.

xqhrs232 wrote:
if i want to use the WM_COMMAND message to dispose the common control's press message.what can i do?

Again, what do you mean? Your original problem was closing the dialog on a
button press, right? I showed you MFC style code that does that. If you want
to use the WM_COMMAND message instead of the button click notification message,
then use it. Same effect. Here's the WM_COMMAND version:

BEGIN_MESSAGE_MAP(CSettingDlg, CDialog)
	ON_COMMAND(IDC_Btn_SetEsc, &CMFCTesterDlg::OnBtn_SetEscCommand)
	ON_WM_CLOSE()
END_MESSAGE_MAP()


LRESULT CSettingDlg::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
//	switch(message)
//	{
//		case WM_COMMAND:
//
//			//I use the button to exit the dialog,which is static create by me!
//			if(wID==IDC_Btn_SetEsc) //static create the button
//			{
//				this->SendMessage(WM_CLOSE,NULL,NULL);
//				return TRUE;
//		
//				//break;
//			}
//
//		case WM_CLOSE:
//			// case WM_DESTROY://2008--4--24 xqh_xg
//			DeleteObjects(); //free the used object
//			break;
//
//	}//switch(message)

	return CDialog::WindowProc(message, wParam, lParam);
} 


void CSettingDlg::OnBtn_SetEscCommand()
{
	PostMessage(WM_CLOSE);
}

void CSettingDlg::OnClose()
{
	DeleteObjects(); //free the used object

	CDialog::OnClose();
}

Anyway, you missed my point in my original post, which was that you needed
to POST the WM_CLOSE message, not SEND it.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

xqhrs23214-May-08 17:13

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

14-May-08 17:13

I think i can capture and dispose the WM_COMMAND message in the Winproc( ) function which is sended by the common control.
my question is that my idea is wrong or not? why sometimes i cannot close the Dialog?what is the matter with my way?
I think my way is the same to your way,but now why my way doesnot work well?

Mark Salsbery14-May-08 18:00

Re: why i cannot close a dialog? the close operation by a button which sendmessage the WM_CLOSE message.

14-May-08 18:00

xqhrs232 wrote:
I think i can capture and dispose the WM_COMMAND message in the Winproc( ) function

MFC does that for you in the code I posted. It does the same thing you are doing
except in an MFC way instead of the Win32 way.

xqhrs232 wrote:
I think my way is the same to your way,but now why my way doesnot work well?

I used PostMessage(), you used SendMessage().

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

xqhrs23215-May-08 0:16

Taking advantage of multi-core procesors??

15-May-08 0:16

you wrote "I used PostMessage(), you used SendMessage()."

you think this is the reason that i cannnot close the dialog sometimes?
if you send WM_CLOSE message,you want to close the dialog right now. so i think i use SendMessage( ) function is a right way.that waits for the result back which we want.so i think i use SendMessage( ) function is no wrong.but the question is that sometimes i can close the dialog correctly but sometimes it doesnot work well!

97C5ENVY8-May-08 11:13

97C5ENVY

8-May-08 11:13

Is there a way to write an application to take advantage of multi-core procesors so that all availble processors (be-it dual-core, quad-core, etc) get equal duty??

Thanks!

CPallini8-May-08 12:33

CPallini

8-May-08 12:33

Threads.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

toxcct8-May-08 21:48

toxcct

8-May-08 21:48

97C5ENVY wrote:
Is there a way

yes, be multithreaded.

but that also means that you'll probably have to be very careful about data synchronization and such problems...

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Michael Schubert8-May-08 21:51

Michael Schubert

8-May-08 21:51

The OS usually assigns the workload to the various cores (or processors). If, for example, you have an application with just a single thread running on a dual core processor, it's quite likely that Windows will spread the work evenly to both cores. In this case, each core would be loaded to approx. 50%.

So, to answer your question, Windows will try to "equalize" the workload for all cores/processors (unless you mess around with affinity settings). However, In order to load the cores to more than 50% (or 25% for a quad), you'll have to create multiple threads in your application (as CPallini pointed out so short and sweet Wink | ;)

Mark Salsbery9-May-08 6:54

9-May-08 6:54

Michael Schubert wrote:
If, for example, you have an application with just a single thread running on a dual core processor, it's quite likely that Windows will spread the work evenly to both cores.

How can a single thread be run simultaneously on multiple cores? Suspicious | :suss:

Just curious,
Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Michael Schubert9-May-08 11:02

Michael Schubert

9-May-08 11:02

Not simultaneously. It's called context switching. The OS manages the thread pool and distributes the workload from all threads among the available cores (be it 1, 2, 4 or 16 cores) in small time intervals.

Mark Salsbery9-May-08 12:18

9-May-08 12:18

Michael Schubert wrote:
distributes the workload from all threads among the available cores (

Right, but you stated "If, for example, you have an application with
just a single thread running on a dual core processor, it's quite likely
that Windows will spread the work evenly to both cores. In this case, each
core would be loaded to approx. 50%.".

So again, how does one thread get split between cores? IME, if you have a thread
that is busy (e.g. in a loop) then one core gets pegged to 100%.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Michael Schubert9-May-08 13:48

Michael Schubert

9-May-08 13:48

Mark Salsbery wrote:
So again, how does one thread get split between cores? IME, if you have a thread
that is busy (e.g. in a loop) then one core gets pegged to 100%.

The OS splits, even a single thread, into "time slices".

If you have a dual core CPU, try it yourself with a single threaded application that puts a heavy load on the CPU and watch how the workload is distributed in Task Manager. It may favour one core but you will see that both are used (unless you set the affinity in Task Manager to use just one core).

Mark Salsbery9-May-08 14:40

9-May-08 14:40

Gotcha. The key part I missed in your previous reply was "Not simultaneously" Smile | :)

Thanks!
Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]