C / C++ / MFC

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

29-Dec-06 7:29

How can this be after an ALT+F4 and getting the entire app closed?

CPallini29-Dec-06 8:18

CPallini

29-Dec-06 8:18

As pointed out by DavidCrow if you allocate dynamically (i.e. using new operator) the Dialog and never delete it then its destructor will never be called, even if the app terminates.
Anyway, maybe posting the code will help...

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.

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

Joan M29-Dec-06 9:20

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

29-Dec-06 9:20

Let me study it a little bit more, but by now what I must say is that adding the override to PostNCDestroy works like charm.

THANK YOU!

David Crow29-Dec-06 7:55

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

29-Dec-06 7:55

Joan Murt wrote:
the dialog was not modal, but in fact, I'm trying to use the PostNCDestroy override function and it seems to work well.

Which means you have a modeless dialog. Do you have something like:

CMyDialog::CMyDialog(CWnd* pParent /*=NULL*/) : CDialog(CMyDialog::IDD, pParent)
{
    Create(IDD);
}
 
void CMyDialog::PostNcDestroy() 
{
    delete this;	
    CDialog::PostNcDestroy();
}
...
CMyDialog *pDlg;
    
pDlg = new CMyDialog;
pDlg->ShowWindow(SW_SHOW);    
...
pDlg->DestroyWindow();

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

Joan M29-Dec-06 9:22

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

29-Dec-06 9:22

Well, it is a little bit more complicated (but not a lot more Wink | ;)

) in fact there are several property sheets that have several property pages that are being created dynamically at runtime.

Then when the main dialog is getting destroyed implicitly the other dialogs that are not modal are being destroyed... As I said it seems to be working... with PostNCDestroy.

David Crow29-Dec-06 7:50

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

29-Dec-06 7:50

Joan Murt wrote:
...I've seen that somehow the destructor of some of the dialogs is not called.

How are you verifying this?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

Joan M29-Dec-06 7:56

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

29-Dec-06 7:56

I do it by placing a breakpoint there... (Moreover I'm changing all my destructors for PostNCDestroy overriden functions and it seems that the memory allocated becomes free).

Gary R. Wheeler30-Dec-06 4:07

Gary R. Wheeler

30-Dec-06 4:07

I'm not sure if this helps, but a common approach with modeless dialogs is for them to delete themselves in their PostNcDestroy() handler, something like this:

// create and show the modeless dialog:
CMyModelessDlg *dlg = new CMyModelessDlg;
dlg->Create(...);
dlg->ShowWindow(SW_SHOW);
//...

CMyModelessDlg::PostNcDestroy()
{
  CDialog::PostNcDestroy();
  delete this;
}

The WM_NCDESTROY message is guaranteed to be the last Windows message sent to the dialog. The PostNcDestroy handler, which is called after the window itself has been destroyed, is the last time a member of the MFC object will be called.

Using this technique, you don't need to keep track of when the user closes the modeless dialog. If you read my sig, you'll notice I've been here before Big Grin | :-D

Software Zen: delete this;

Fold With Us![^]

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

Joan M30-Dec-06 4:39

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

30-Dec-06 4:39

Nice thing to know, and yes, it seems a software zen Wink | ;)

The thing here is that al the dialogs are not really dialogs, they are property pages...

But again, nice to know that.

Thank you.

Joan M30-Dec-06 4:41

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

30-Dec-06 4:41

Should I free everything before CDialog::PostNcDestroy(); or there is no difference if I do it before or after?

I'm not sure, but could it be interesting to delete/free all the members of that dialog before CDialog::PostNcDestroy(); and delete this; just after?

Thank you in advance.

Gary R. Wheeler30-Dec-06 8:29

Gary R. Wheeler

30-Dec-06 8:29

Generally speaking, I do my cleanup before the CDialog::PostNcDestroy() call. This sort of makes sense, since the calling the base class PostNcDestroy() function passes the operation 'up' the hierarchy, and any derived version of that operation should be completed first.

I use PostNcDestroy() for things like calling DeleteObject on loaded resources (bitmaps, icons, fonts, etc.). I try to make it a practice to restore the MFC object to its initialized state, in the case user of the object is going to recreate the Window that the object manages.

Software Zen: delete this;

Fold With Us![^]

Re: VC++6 : MFC and dialog based app: how can I ensure that a dialog destructor will be called?

Joan M30-Dec-06 8:36

scan string for characters \ / ? * : "

30-Dec-06 8:36

Great, thank you again.

rolfhorror29-Dec-06 6:05

rolfhorror

29-Dec-06 6:05

any easy way to scan a string that a user inputs in an editbox control,
for characters and remove them from the string?

charachters like: \ / ? * : " < > |

say i have this function...

void CMyDlg::OnCheck()
{
GetDlgItemText(IDC_EDIT1, str);

//do a scan of the string to see if it contains the characters \ / ? * : " < > |
//remove them from the string
//return the string without the characters

MessageBox("Your string: "+str,"");
}

or any other way to only let the user input only a-z and A-Z characters in the editbox?

thanks.

Joan M29-Dec-06 6:49

29-Dec-06 6:49

you can take advantage of CString.

There is a member function that wil automatically remove the chars or substrings that you pass to it.

I think it's called .Remove("");

You should call:

UpdateData();
editboxstring.Remove("/");

From the MSDN:

CString::Remove
int CString::Remove( TCHAR ch );

Return Value

The count of characters removed from the string. Zero if the string isn't changed.

Parameters

ch

The character to be removed from a string.

Remarks

Call this member function to remove instances of ch from the string. Comparisons for the character are case-sensitive.

Example

//remove the lower-case letter 't' from a sentence:

CString str("This is a test.");
int n = str.Remove('t');
ASSERT(n == 2);
ASSERT(str == "This is a es.");

rolfhorror29-Dec-06 7:24

rolfhorror

29-Dec-06 7:24

thanks, this really helped a lot, it worked like a charm.

CPallini29-Dec-06 6:52

CPallini

29-Dec-06 6:52

have a look at CString::Remove.
Smile | :)

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.

Michael Dunn29-Dec-06 7:00

Michael Dunn

29-Dec-06 7:00

CString::Remove() will do that, although you'll need to call it once for each character.

--Mike--
Visual C++ MVP Cool | :cool:

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David Crow29-Dec-06 7:48

29-Dec-06 7:48

hobbyprogrammer wrote:
//do a scan of the string to see if it contains the characters \ / ? * : " < > |
//remove them from the string
//return the string without the characters

Why not just disalloow them to begin with?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

unsigned char (*) warning msg

James R. Twine29-Dec-06 9:27

James R. Twine

29-Dec-06 9:27

hobbyprogrammer wrote:
or any other way to only let the user input only a-z and A-Z characters in the editbox?

You can have look at http://www.codeproject.com/editctrl/enhfocusedit.asp[^] for some ideas on how to filter the input.

Peace!

-=- James

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ikbahrian29-Dec-06 2:42

ikbahrian

29-Dec-06 2:42

could anyone please guide me how can i get rid of the warning messges-

warning: format '%s' expects type 'char *', but argument 3 has type 'unsigned char (*)[3]'
warning: pointer targets in passing argument 1 of 'strlen' differ in signedness
---------------------------
struct test
{
unsigned char cont_type[3];
}

hits = sscanf(argv[i], "%s",&(test.cont_type));
printf("\nSending test packets with %s.\n", test.cont_type);
if(strlen(test.cont_type)>3)
------------------
thx

CPallini29-Dec-06 3:13

CPallini

29-Dec-06 3:13

it seems that you want to store some kind of string inside cont_type.
Holding that hypothesis, I cannot understand why are you passing &(test.cont_type), instead of (char *)test.cont_type. Note the cast that is needed also in the following statements in order to suppress the warning.

Hope that helps.

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.

ikbahrian29-Dec-06 3:29

ikbahrian

29-Dec-06 3:29

thanks.. I change the data type of cont_type from unsigned char to char...and it works..

David Crow29-Dec-06 3:22

29-Dec-06 3:22

ikbahrian wrote:
hits = sscanf(argv[i], "%s",&(test.cont_type));

test.cont_type is already an address, so there is no need to preface it with the address-of operator.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb