C / C++ / MFC

Problems with Overriding OnOK() and OnCancel()

6-Mar-09 22:18

I tried a few more things, but can't get it to work. Still missing something here. Please help!

In the main dialog header I have addded the OnOK() and OnCancel() virtual functions manually to the area where the wizard had already put its virtual function for the DoDataExchange() override, is that the correct place?

//{{AFX_VIRTUAL(CTestDlg)
	protected:
	virtual void DoDataExchange(CDataExchange* pDX);	// DDX/DDV-Unterstützung
	virtual void OnOK();
	virtual void OnCancel();
	//}}AFX_VIRTUAL

Then I have added the ON_WM_CLOSE() message like this in the .cpp file of the main dialog:

BEGIN_MESSAGE_MAP(CTestDlg, CDialog)
	//{{AFX_MSG_MAP(CTestDlg)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_CONNECT, OnConnect)
	ON_NOTIFY(TCN_SELCHANGE, IDC_Test_MENUS, OnSelchangeTestMenus)
	ON_BN_CLICKED(IDC_OK, OnOk)
	ON_BN_CLICKED(IDC_TestHELP, OnTesthelp)
	ON_BN_CLICKED(IDC_SETTINGS, OnSettings)

	ON_WM_CLOSE()

	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

But I am stuck now. Any hints would be most appreciated.

B_U_A7-Mar-09 16:17

Re: Simple Noob Question: Problem with "CONTROL PARENT" setting in tabbed dialog

7-Mar-09 16:17

Is there anyone, who could give me some hints/examples as to the problems I have with overriding the OnOK() and OnCancel() function, as per this thread?
Many thanks in advance Wink | ;-)

Nishad S8-Mar-09 5:31

Re: Simple Noob Question: Problem with "CONTROL PARENT" setting in tabbed dialog

8-Mar-09 5:31

Alt+F4 is same as closing the window by clicking close button. As I said before, you should map WM_CLOSE and call EndDialog there. To map the WM_CLOSE, take the ClassWizard, select the WM_CLOSE for your dialog class, and add it.

- ns ami -

B_U_A9-Mar-09 1:03

Re: Simple Noob Question: Problem with "CONTROL PARENT" setting in tabbed dialog

9-Mar-09 1:03

Thanks for reiterating your advice. The problem I have is that I don't know how to do it properly?
Do I understand you right in that not only the Close button in the title bar (X) as well as the ALT+F4 key combination, BUT ALSO hitting the ESC key or the ENTER key, any of these four events would trigger an WM_CLOSE message?

I gave it a go and as per your post I have added ON_WM_CLOSE using the ClassWizard (see excerpt of header below)...

//{{AFX_MSG(CTestDlg)
        virtual void OnOK();
	afx_msg void OnClose();
	//}}AFX_MSG
	DECLARE_MESSAGE_MAP()
private:

...and it is also in the message map in the *.cpp file:

BEGIN_MESSAGE_MAP(CTestDlg, CDialog)
	//{{AFX_MSG_MAP(CTestDlg)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_WM_CLOSE()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

However when running the application, the ESC key as well as the ENTER key are still closing the program. So that didn't really do the trick.
I would appreciate if you could please specify a bit more detailed.
Many thanks Wink | ;-)

Nishad S9-Mar-09 2:06

Re: Simple Noob Question: Problem with "CONTROL PARENT" setting in tabbed dialog

9-Mar-09 2:06

Let me make things clear...

Overriding the OnOK and OnCancel and keeping them blank (like void OnOK() { /*nothing to do*/ } ) will avoid the processing of Enter key and Escape key hits.

Clicking the close button or pressing Alt+F4 will send WM_CLOSE message to the window/dialog. In dialog, it will call the OnClose, if mapped. Its default implementation will send the WM_COMMAND with IDCANCEL inturn the OnCancel will be called. So when the OnCancel is overridden and kept doing nothing, will cause the dialog unable to be closed. So in this scenario, the OnClose should be implemented and the EndDialog should be called explicitly, instead of calling CDialog::OnClose().

So if my understandings about your problems are correct, you have to override the OnOK, OnCancel and OnClose (in the main dialog). The OnOK and OnCancel should be kept blank. And in the OnClose you have to call EndDialog().

If you are still facing problem, please let me know.

- ns ami -

B_U_A9-Mar-09 23:50

Re: Simple Noob Question: Problem with "CONTROL PARENT" setting in tabbed dialog

9-Mar-09 23:50

Dear -ns ami- ...many thanks for your detailed reply, which was very helpful.
It now makes perfect sense to me and I think I have a much better understanding of the whole WM_xxx stuff and about overriding virtual functions.

What you explained works fine now; exactly in the way I wanted it.
I am grateful that you took the time to write everything down.

Can I ask one more question (for now Wink | ;-)

), please?

I have added a button and upon clicking this (&Close) button I want to shut down the application. I thought I just grab the ON_BN_CLICKED (the ID is IDC_OK) and map/call the same function OnClose, as the one that the ON_WM_CLOSE calls, ... like the // line below:

	ON_BN_CLICKED(IDC_SETTINGS, OnSettings)
	ON_WM_CLOSE()
//	ON_BN_CLICKED(IDC_OK, OnClose)
	ON_BN_CLICKED(IDC_OK, OnAbort)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

...but that wasn't such a good idea, because then the Class Wizard complains with a 'PARSER ERROR'.

So as a next step I have added the
ON_BN_CLICKED(IDC_OK, OnAbort) map entry and then further down the member function like this:

void CTestDlg::OnClose()	
{
	EndDialog(true);	
}

void CTestDlg::OnAbort() 
{
	EndDialog(true);	
}

What I don't like is that I now have twice the same code (...calling the EndDialog()).
Is that the right way of doing it? Or am I missing something here again, ... and I can actually (somehow) map the button event to the same OnClose member function?
If so, how?

Thanks again in advance.

Nishad S10-Mar-09 23:44

Re: Simple Noob Question: Problem with "CONTROL PARENT" setting in tabbed dialog

10-Mar-09 23:44

Sorry for the late reply...

There is no problem in calling EndDialog() from multiple functions.
But if you want to do something in common before application exits, then the following method will be useful.

void CTestDlg::AppShutDown()
{
    // Some codes...
    SaveSettings();

    EndDialog( 0 );
}

void CTestDlg::OnClose()
{
    AppShutDown();
}

void CTestDlg::OnAbort()
{
    AppShutDown();
}

- ns ami -

B_U_A12-Mar-09 22:32

Re: Simple Noob Question: Problem with "CONTROL PARENT" setting in tabbed dialog

12-Mar-09 22:32

Many thanks ns ami,
...you don't have to apologise at all; I find it very nice from you to even answer my beginner's questions.
Thanks for the idea with 'bundling' functions in the way you describe - good idea! Smile | :)

I might try that, ...see how my little project goes.

Nishad S13-Mar-09 1:59

Re: creating toolbar for IE

13-Mar-09 1:59

B_U_A wrote:
Many thanks ns ami,

You are welcome... Smile | :)

- ns ami -

creating toolbar for IE

Ash_VCPP5-Mar-09 22:08

Ash_VCPP

5-Mar-09 22:08

can someone tell me where i can get a good and very simple tutorial to create toolbar for IE using atl/com....i quite surprised coz after googling i didnt get one useful tutorial......i need it so that i can have a skeleton to start making mine.....

Thanks A Ton
Ash_VCPP

SandipG 5-Mar-09 22:16

SandipG

5-Mar-09 22:16

Ash_VCPP wrote:
i quite surprised coz after googling i didnt get one useful tutorial..

This is the first link i got after googling IE toolbar tutorial [^]

I hope it helps.

Regards,
Sandip.

Re: creating toolbar for IE

Ash_VCPP5-Mar-09 22:19

Ash_VCPP

5-Mar-09 22:19

hi sandip,
Thanks for the reply....i already saw that one but its too big to understand actually i am looking to get very basic and simple one just for starting...and further coding i will do according to my requirement.

Thanks A Ton
Ash_VCPP

Re: creating toolbar for IE

Hamid_RT6-Mar-09 0:25

Hamid_RT

6-Mar-09 0:25

Codeproject.

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

what is "commit storage" any way?

JackPuppy5-Mar-09 21:09

JackPuppy

5-Mar-09 21:09

in the fifth edition of Windows via C/C++(written by Jeffery Richter)
in many places i saw this phrase "commit storage", for example in Chapter 17, section "Memory-Mapped Executables and Dlls", there is this note:

" When a process is loaded, the system examines all the file image's pages. The system commits storage in the paging file immediately for pages that would normally be protected with the copy-on-write attribute. These pages are simply committed; they are not touched in any way. When a page in the file image is accessed, the system loads the appropriate page. If that page is never modified, it can be discarded from memory and reloaded when necessary. If the file's page is modified, however, the system swaps the modified page to one of the previously committed pages in the paging file."

what does he mean by "commit storage"? What if a page is committed? What does the system do to commit a page? what does this sentence mean "If the file's page is modified, however, the system swaps the modified page to one of the previously committed pages in the paging file."

Can somebody help me?
Thanks!

Jack

Re: what is "commit storage" any way?

Eytukan5-Mar-09 22:39

Eytukan

5-Mar-09 22:39

Committed means the memory that is ready for use. It's at the disposal.

JackPuppy wrote:
When a page in the file image is accessed, the system loads the appropriate page. If that page is never modified, it can be discarded from memory and reloaded when necessary.

You should know about Paging to understand these terminologies. That's Bascically about maintaining virtual memory. To trick your process to believe it's got 2GB of address at it's disposal. You might have heard every process in windows is allocated a virtual memory of 2GB for userspace. But they are "virtual". Even you have just 512 KB of virtual memory, your process can use upto 2GB - because of memory gets mapped to virtual memory. Here the chunks of memory are termed as "pages". In the quoted text, what it means is that, until a specific page from your application is not required, it's not loaded into memory. And the pages that the OS predicts to be required would be kept in the page file (VM). If the application searches for a page that is not found the the physical memory(RAM), it searches the page files table & loads the required page. And if the phyiscal memory is full, it does a swapping based on some page replacement algorithms. Ok enough of the story, Search for "Paging" &"virtual memory". May be you can add "win32" if are specific about the OS implementation. byebye. Thumbs Up | :thumbsup:

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Re: what is "commit storage" any way?

JackPuppy5-Mar-09 23:22

JackPuppy

5-Mar-09 23:22

Wow, thanks， a great answer.

After my searching and reading, it should be pointed out that if the application searches for a page that is not found in the RAM, sometimes it will search for exe/dll file somewhere in disk other than page file,for example when the exe/dll file mapped into process address without relocation-that means it doesn't need page files to store relacated pages.

Thanks for your kind!

Resizing CListCtrl

grassrootkit5-Mar-09 20:49

grassrootkit

5-Mar-09 20:49

I'm handling ::OnSize() of my CView and I want my CListCtrl resize accordingly .

void CMyView::OnSize(UINT nType, int cx, int cy)
{
	RECT rc;
        //this->GetWindowRect(&rc);
	POINT p;
	p.x = cx;
	p.y = cy;
	//ClientToScreen(&p);
       	GetClientRect(&rc);
//     	m_cMyList.SetWindowPos(NULL,0,0,rc.cx,cy,1);
       	m_cMyList.SetWindowPos(NULL,0,0,rc.right,rc.bottom,1);
	
}

As you see I tried out damn things [Of course the wrong way!]. Nothing works. Any help?

SandipG 5-Mar-09 21:04

SandipG

5-Mar-09 21:04

Check SetWindowPos[^] documentation.

grassrootkit wrote:
m_cMyList.SetWindowPos(NULL,0,0,rc.right,rc.bottom,1);

Here instead of NULL you should specify &CWnd::wndTop because it seems that it is the only control on your dialog.

Also last parameter instead of 1 pass SWP_SHOWWINDOW i am not sure 1 is defined for which constant.

grassrootkit wrote:
GetClientRect(&rc);

You do not need this instead you can use cx,cy parameters. I think you doing this because first time when you get the WM_SIZE notification these values are zero. You can simply put a check for that instead of that call.

Also when you resizing the window in OnSize always verify the m_cMylist has valid handle and it is visible. This should be done because WM_SIZE notification is sent multiple times when the main window is being created.
I hope it helps.

Regards,
Sandip.

grassrootkit5-Mar-09 21:54

grassrootkit

5-Mar-09 21:54

SandipG wrote:
SWP_SHOWWINDOW

Does the matter. I put 1 just to quickly test the functionality. What a crap. This wasted almost half an hour. Thanks for pointing it out. Thumbs Up | :thumbsup:

Code-o-mat5-Mar-09 22:47

Code-o-mat

5-Mar-09 22:47

Actually he may specify NULL as the first parameter and use the SWP_NOZORDER flag to indicate he doesn't wish to change the Z-order of the window...

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

SandipG 5-Mar-09 23:05

SandipG

5-Mar-09 23:05

Yes.. i forgot about the SWP_NOZORDER Smile | :)

Regards,
Sandip.