C / C++ / MFC

jhwurmbach30-Aug-07 22:12

30-Aug-07 22:12

You are right, in an implicit, conceptual way, the STL *uses* ihheritance. Or rather common concepts implemented in differnet classes - like iterators.
But it does not use inheritance in the C++-sense, which was the point to make to the OP.

emilio_grv wrote:
Unfortunately for STL, in all the cases where value semantics is not desirable (i.e: A is a huge structure you don't want to continuously copy),

In this case, I would use smart-pointers anyway. Preferably in some Interface-based-programming-style.

emilio_grv wrote:
or when classic C++ inheritance is needed, (you need proper translation units, not template instantiation)

Yes - STL-containers in module interfaces are very tricky. E.G. in a DLL-interface: sometimes it works, sometimes not.

Though I speak with the tongues of men and of angels, and have not money, I am become as a sounding brass, or a tinkling cymbal.
George Orwell, "Keep the Aspidistra Flying", Opening words

Emilio Garavaglia30-Aug-07 22:44

Emilio Garavaglia

30-Aug-07 22:44

jhwurmbach wrote:
In this case, I would use smart-pointers anyway

Sure. but this introduce a level of indirection that influence the algorithm semantics
(like

for(mylist::iterator i=alist.begin(); i!=alist.end(); ++i) (**i).do_something(.);

)
(note there's two "*", so the algorithm where the "for" is, must be designed to track that,
or you've to design algorithms to have an extra "traits" parameter to define how to handle the dereference e the dereferenced type, that list is not directly aware of).
in other words, there is always something missing, whether the approach is.

What we can do is choose what to miss.

2 bugs found.
> recompile ...
65534 bugs found.
D'Oh! | :doh:

jhwurmbach30-Aug-07 22:48

30-Aug-07 22:48

emilio_grv wrote:
in other words, there is always something missing, whether the approach is. What we can do is choose what to miss.

There is something deeply philosophical in this words.
Rose | [Rose]

But yes, you are right: There is no one size fits all - Tool. Which makes much of our qualification. Big Grin | :-D

Though I speak with the tongues of men and of angels, and have not money, I am become as a sounding brass, or a tinkling cymbal.
George Orwell, "Keep the Aspidistra Flying", Opening words

Emilio Garavaglia30-Aug-07 22:15

Emilio Garavaglia

30-Aug-07 22:15

you're talking about a "type-dependent" type.
Templates are the right way to go.

2 bugs found.
> recompile ...
65534 bugs found.
D'Oh! | :doh:

Edit box

Kiran Pinjala30-Aug-07 20:21

Kiran Pinjala

30-Aug-07 20:21

I wanto an edit box which takes only numbers and special character.
Is there a property that can be set like we have 'numbers' or do i have to make my logic inside?

KIRAN PINJARLA

Nishad S30-Aug-07 20:44

Nishad S

30-Aug-07 20:44

A raw sample code for filtering the space may look like...

BOOL CTestDlg::PreTranslateMessage(MSG* pMsg)
{
if( pMsg->message == WM_KEYDOWN )
{
if( pMsg->hwnd == GetDlgItem( IDC_EDIT1 )->m_hWnd )
{
if( pMsg->wParam == VK_SPACE )
{
pMsg->message = WM_NULL;
}
}
}
return CDialog::PreTranslateMessage(pMsg);
}

- NS -

chandu00430-Aug-07 20:51

30-Aug-07 20:51

you do have to write your own logic for that.
i can share it with you if you come back with the actual requirement with an example.

Re: Edit box [modified]

Kiran Pinjala30-Aug-07 21:10

Kiran Pinjala

30-Aug-07 21:10

I have to create login codes which will contain only numbers and special characters like *,#,$,+,-. So i want the edit control to accept only therse characters and numbers.

-- modified at 3:16 Friday 31st August, 2007

KIRAN PINJARLA

Re: Edit box [modified]

chandu00430-Aug-07 21:18

30-Aug-07 21:18

use onchange event of the edit box.
in that box, keep scanning the string available in the edit box.
there if you find any un required character,
simply, update the edit box with a new string, which omits that character.
ultimately, you will get the output as if the un desired characters are not being taken by the control.

-- modified at 3:37 Friday 31st August, 2007

6Qing8830-Aug-07 21:31

6Qing88

30-Aug-07 21:31

Windows hooking mechnism may be desired to solve your problem.

Nishad S30-Aug-07 21:34

Nishad S

30-Aug-07 21:34

I am afraid that is bulky... since there are simple solutions.

- NS -

jhwurmbach30-Aug-07 21:34

30-Aug-07 21:34

Why?
Wouldn't subclassing be much easier?

Though I speak with the tongues of men and of angels, and have not money, I am become as a sounding brass, or a tinkling cymbal.
George Orwell, "Keep the Aspidistra Flying", Opening words

jhwurmbach30-Aug-07 21:36

30-Aug-07 21:36

kiran.pinjarla wrote:
I wanto an edit box which takes only numbers and special character.

You can have a edit box that takes only numbers. No way of inserting "-1.0".
Useless crap. One of the larest omissions in the Windows GUI-classes.

For usable numeric edit fields, scan the "controls"-section of codeproject.

Though I speak with the tongues of men and of angels, and have not money, I am become as a sounding brass, or a tinkling cymbal.
George Orwell, "Keep the Aspidistra Flying", Opening words

Anurag Gandhi30-Aug-07 23:41

Anurag Gandhi

30-Aug-07 23:41

Create a new class with base class CEdit and override the OnChar event handler.

void CharEdit::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags)
{
if ( (nChar >= 65 && nChar <= 90) || (nChar >= 97 && nChar <= 122))
{
MessageBeep ( 0 ) ;
return ;
}

CEdit::OnChar(nChar, nRepCnt, nFlags);
}

Thats it.

Anurag Gandhi.
http://www.softgandhi.co.nr
Life is a computer program and every one is the programmer of his own life.

Iain Clarke, Warrior Programmer

Iain Clarke, Warrior Programmer31-Aug-07 0:05

31-Aug-07 0:05

Search for Masked Edit controls on CP, there are a bunch of articles doing subclassed edit controls to do what you want.

Iain.

WaitForSingleObject Not working.. Help Plzz

megha_gharote30-Aug-07 20:09

megha_gharote

30-Aug-07 20:09

Dear Friends,

Using a thread i m writting a file and i want to wait untill the file is written.
For this i have used WaitForSingleObject but its not working..
here is the code

MAIN FILE
pApp->m_hEvent = ::CreateEvent(NULL, FALSE, FALSE, "FileEvent");
pSLMDoc->UpdateJobOrderInfo(m_pJobOrderInfo);
WaitForSingleObject(pApp->m_hEvent, INFINITE);
if (file.Open(strFileName, CFile::modeRead, &e) == FALSE)
{
AfxMessageBox(e.m_cause);
}
UINT nRet = file.Read(pFileJobOrder, sizeof(FILE_JOBORDER));

IN THREAD FILE
CBackupFile file;
file.WriteFile(pDBJobOrder);
delete pDBJobOrder;
::SetEvent( ((CSLMApp*) AfxGetApp())->m_hEvent );
return;

It is not wating till the time file writing is going on. And then it will throw an error in file opening..

Can u plz help me.. if u need any more input plzz tell me Cry | :((

Megha

some more details required ot solve.

chandu00430-Aug-07 20:19

30-Aug-07 20:19

definitely, i can solve this coz, i also faced these such problems in past.
but please let me know the purpose and architecture of your program.

megha_gharote30-Aug-07 20:31

megha_gharote

30-Aug-07 20:31

In Main File
In my application on click of a button, i'l check if DB connection is there. if its not then
pApp->m_hEvent = ::CreateEvent(NULL, FALSE, FALSE, "FileEvent");
pSLMDoc->UpdateJobOrderInfo(m_pJobOrderInfo); //This fuction starts a thread to write a file.

In the thread File
CBackupFile file;
file.WriteFile(pDBJobOrder); //Calls a fuction to write a file
delete pDBJobOrder;
::SetEvent( ((CSLMApp*) AfxGetApp())->m_hEvent ); // Set the event
return;

I want to wait untill this thread executes.. but it is not happening...
Did u get my problem..

megha

chandu00430-Aug-07 20:39

30-Aug-07 20:39

you mean, you want to wait in the button till the thread comletes. am i right?

Mark Salsbery30-Aug-07 20:39

Mark Salsbery

30-Aug-07 20:39

Often, if you have/want to wait for another thread to execute, you don't need another thread.

If the creating thread can't continue executing until the second thread finishes, do you
really need another thread?

Mark

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

solution

chandu00430-Aug-07 20:44

30-Aug-07 20:44

try to follow this algorithm.
int flag=0;//global variable
button code
{
pApp->m_hEvent = ::CreateEvent(NULL, FALSE,
FALSE, "FileEvent");
pSLMDoc->UpdateJobOrderInfo(m_pJobOrderInfo); //This
fuction starts a thread to write a file.
while(flag==0);//wait till flag is made 1.
}
thread code
{
//perform your writing here
then at the end of the thread, make flag=1;
}
}

Re: solution

megha_gharote30-Aug-07 21:07

megha_gharote

30-Aug-07 21:07

I tried this one
It is working.

Thank u

Re: solution

Nishad S30-Aug-07 21:11

Nishad S

30-Aug-07 21:11

If this is the solution, then what is the use of events... Laugh | :laugh:

- NS -

Re: solution

chandu00430-Aug-07 21:20

30-Aug-07 21:20

please rename this message subject by prefixing [solved] to the subject
thanx