C / C++ / MFC

mikeh31-May-02 5:00

mikeh

31-May-02 5:00

Not directly. The code is housed within a COM component that contains a doc-view framework. The user clicks a toolbar button that creates an instance of a modeless dialog. When the mouse is moved over the dialog items (ie. OnMouseMove()), the example code is triggered to determine what control the mouse is over. The error is an 005 Access Violation which usually means a bad pointer. I'm not sure why the code works fine in debug. I suspect it has something to do with the individual controls. I used classwizard to define member variables for each control. I get further into the code now, but, it still crashes later on. In release mode, it appears that the GetDlgItem() call has trouble if the control is not tied to an actual member variable.

31-May-02 5:35

Pretty sure you should use "AFX_MANAGE_STATE (AfxGetStaticModuleState ());" at the beginning of the COM call - especially if your using CWnds or resources (or any MFC!) inside a DLL.

mikeh31-May-02 7:47

mikeh

31-May-02 7:47

Thanks to Mike Collins, this problem has been solved. Here is the resolution:

My code uses many user message handlers. I typically use the ON_MESSAGE() macro with a function handler. When defining the function handler, I often code a prototype function like the following:

void OnUserHandler();

However, this is incorrect. Eventhough this code will compile (with no warnings!) and work fine in debug, it will fail in release mode. The resolution is to change the function handlers to the following:

afx_msg LRESULT memberFxn(WPARAM, LPARAM);

Hope this helps all who run across this in the future!

Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

James R. Twine31-May-02 10:33

James R. Twine

31-May-02 10:33

FWIW, the version of MFC included with VS.NET uses the casting operators to detect when signature mismatches like this occur.

Peace!

-=- James.
"Some People Know How To Drive, Others Just Know How To Operate A Car."
(Try Check Favorites Sometime!)

Munkijo31-May-02 2:01

Munkijo

31-May-02 2:01

I have a CString type variable with a large HTML file in it. When I attempt to replace all occurrances of a character with another characer, it works fine, however, if I attempt to replace a string ("= ") with another string ("="), it appears to get stuck in some endless loop somewhere.

I have left it running for hours, and it is still stuck at the same replace statement. Is there something I'm missing?

Re: Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

Mazdak31-May-02 2:34

Mazdak

31-May-02 2:34

Whats your code?

Mazy

"The more I search, the more my need
For you,
The more I bless, the more I bleed
For you."The Outlaw Torn-Metallica

Re: Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

Munkijo31-May-02 7:27

Munkijo

31-May-02 7:27

It's not a very elegant method, but the code is:

void CParser::StandardiseHTML ( CString* HTMLfile )
{
HTMLfile->Replace ("@", "@");
HTMLfile->Replace ('\n', ' ');
HTMLfile->Replace ('\t', ' ');
HTMLfile->Replace (" ", " ");

while ( HTMLfile->Replace (" ", " ") != 0 );

HTMLfile->Replace (" =", "=");
HTMLfile->Replace ("= ", "=");
HTMLfile->MakeUpper ();
}

It manages to get into trouble with the statement

HTMLfile->Replace (" ", " ");

Re: Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

Munkijo31-May-02 7:33

Munkijo

31-May-02 7:33

What??? No, where it says

HTMLfile->Replace (" ", " ");

the first string is actually a non-braking space character - In the while loop, it's meant to have two spaces between the first seyt of inverted commas, and one in the second set.

Re: Problem with CString::Replace ( LPCTSTR lpszOld, LPCTSTR lpszNew );

Bill Wilson31-May-02 14:22

Bill Wilson

31-May-02 14:22

Is it possible the first character is actually a space just like the second? That would cause an infinite loop, as each call to replace will find the same character and replace it with itself.

To Release or Not to Release...

Braulio Dez31-May-02 0:59

Braulio Dez

31-May-02 0:59

Hi,

Sometimes, I feel a little bit lost with COM, and QI AddRef Release, smart pointers, long pointers to...., just two case:

Should I Release this pointer or not ?

LPDISPATCH pDisp = Fmt.GetObject(); // Fmt is from Ms Word WD::OLEFormat Fmt

And in this case ?

BSREPORTCTRLSLib::IBsMetafile *pIBsMeta;
pDisp->QueryInterface(IID_IBsMetafile, (void **) &pIBsMeta);

Thanks, Greetings
Braulio

Tomasz Sowinski31-May-02 1:21

31-May-02 1:21

[edited - I shouldn't watch FIFA World Cup and answer questions at the same time]
You should use Release when you're done with interface returned from QueryInterface call.

Have no idea about GetObject.

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

Len Holgate31-May-02 1:21

Len Holgate

31-May-02 1:21

QI calls AddRef() on your behalf internally, calling it again on the returned pointer means you now have 2 references on the interface pointer and need to call Release() twice...

See: ATLBase.h 5374 (your line numbers may vary Wink | ;)

) for an example QI implementation:

ATLINLINE ATLAPI AtlInternalQueryInterface(
   void* pThis,
   const _ATL_INTMAP_ENTRY* pEntries, 
   REFIID iid, 
   void** ppvObject)
{
   ATLASSERT(pThis != NULL);
   // First entry in the com map should be a simple map entry
   ATLASSERT(pEntries->pFunc == _ATL_SIMPLEMAPENTRY);
   if (ppvObject == NULL)
      return E_POINTER;
   *ppvObject = NULL;
   if (InlineIsEqualUnknown(iid)) // use first interface
   {
      IUnknown* pUnk = (IUnknown*)((int)pThis+pEntries->dw);
      pUnk->AddRef();
      *ppvObject = pUnk;
      return S_OK;
   }
...

Len Holgate
www.jetbyte.com
The right code, right now.

Tomasz Sowinski31-May-02 2:29

31-May-02 2:29

This happens when you watch a game and surf CP. Anyway, Senegal leads 1 Blush | :O

after first half Wink | ;)

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

Len Holgate31-May-02 2:28

Len Holgate

31-May-02 2:28

Len Holgate
www.jetbyte.com
The right code, right now.

Len Holgate31-May-02 1:16

Len Holgate

31-May-02 1:16

Braulio Díez wrote:
Should I Release this pointer or not ?

LPDISPATCH pDisp = Fmt.GetObject(); // Fmt is from Ms Word WD::OLEFormat Fmt

Yes. A function has returned you an interface, it will have called AddRef() before it returned it to you, you now own a reference to the interface and should call Release() when you're done with it.

Braulio Díez wrote:
And in this case ?

BSREPORTCTRLSLib::IBsMetafile *pIBsMeta; pDisp->QueryInterface(IID_IBsMetafile, (void **) &pIBsMeta);

Again, yes. You've called QI, that results in the interface that is returned to you being AddRef()'d, you now own a reference to the interface and should call Release().

In both cases you have bare interface pointers so you're responsible for managing the reference counts. Generally, if you have bare pointers and a function returns you an interface you need to call Release() when you're done.

Len Holgate
www.jetbyte.com
The right code, right now.

a question of edit control

Mauricio Ritter31-May-02 1:35

Mauricio Ritter

31-May-02 1:35

Every reference to an interface needs to be released...

Mauricio Ritter - Brazil
Sonorking now: 100.13560 Trank

Beer | [beer]

The alcohol is one of the greatest enemys of man, but a man who flee from his enemys is a coward. Beer | [beer]

31-May-02 0:55

when I click in my editbox,I want all the contents to be
selected,I used these code:
void CCaculatorDlg::OnSetfocusEDITap1()
{
CEdit* ped=(CEdit*)GetDlgItem(IDC_EDIT_ap1);
ped->SetSel(0, -1, FALSE);

}
but it doesnt work, when I click at the editbox, it
just like havent added these code.
what could I do?

User 665831-May-02 4:45

User 6658

31-May-02 4:45

Did you try handling GetFocus instead of SetFocus?

modified 12-Sep-18 21:01pm.

ilavl31-May-02 17:07

ilavl

31-May-02 17:07

but there's no message like GetFocus,
(I look it up in class wizard)

valikac31-May-02 5:15

valikac

31-May-02 5:15

Use EN_SETSEL

-----

// editHWnd is the handle to your edit control
// from and to are the beginning and end of your select range

SendMessage(editHWnd, EM_SETSEL, static_cast<wparam>(from),
static_cast<lparam>(to));
-----

Kuphryn

Tomasz Sowinski31-May-02 5:32

31-May-02 5:32

There's no EN_SETSEL.

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

valikac31-May-02 5:27

valikac

31-May-02 5:27

I meant EM_SETSEL.

Kuphryn

Tomasz Sowinski31-May-02 5:38

31-May-02 5:38

And what do you think CEdit::SetSel does?

Tomasz Sowinski -- http://www.shooltz.com

- It's for protection
- Protection from what? Zee Germans?

valikac31-May-02 5:36

valikac

31-May-02 5:36

There are more than one way to get it working. Using EM_SETSEL is another method. I recommend trying that method to see if get the design where you want it.

Kuphryn

Tomasz Sowinski31-May-02 6:01