C / C++ / MFC

Re: Different methods in objects in a List [modified]

18-Mar-08 3:00

piul wrote:
The question is, how do I implement a GetOrientation() function in CNode??

Probably the scenario will be clearer if you answer to the question "Why CNode needs to call GetOrientation?". I.e. must CNode retrieve always meaningful info with such a call?

Generally speaking, there are two viable methods to overcome the problem:
(1) use RTTI[^] to identify the actual type of the item.
(2) go through polymorphism: declare a pure virtual GetOrientation method
in CItem class thus forcing both CEmboss and CAnneal to implement it.

Personally I don't like method (1), but, of course, we have to choose the one that better fit our needs...

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.

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

Member 75496020-Mar-08 5:25

Member 754960

20-Mar-08 5:25

This pattern presents a maintenance problem to me. What happens when you add more CItem types? How useful is CNode if the code needs to detect the type of the contents?

The solution to me is to specialize the CNode class for the different CItems it holds,

// generic class
class CNode
{
public:
	virtual bool process() = 0
	{
		// common default function
	}
};

class CEmbossNode : public CNode
{
public:
	virtual bool process()
	{
		// access CItem or CEmboss data/functions
		return CNode::process();	// or call default
	}
protected:
	int GetOrientation() const  { return mnOrient; }
private:
	int mnOrient;
	CEmboss * mpItem;
}

class CAnnealNode : public CNode
{
public:
	virtual bool process()
	{
		// access CItem or CAnneal data/functions
		// or call default
	}
private:
	CAnneal * mpItem;
};

class CList
{
	// ...
	CNode * mpListHead;
}

The types are hidden behind a polynorphic interface. Adding new types requires the definition of the polymorphic interface. Each CItem knows what it is and can use special knowledge or do just the default action.

IMHO, these outwiegh the cost of the virtual function.

// edit: remove multiple EmbossNode declarations

modified on Monday, March 24, 2008 1:43 PM

Drawing pictures c++ win32

Hanan88818-Mar-08 1:45

Hanan888

18-Mar-08 1:45

I'm developing a game, but the graphics are simple pictures that I show, without any further graphical functionality.

I need to know what simple ways I have to show pictures.

I tried DirectX 9 textures, but it took a lot of loading time.

I'm trying using CImage but something goes wrong.
Specifically, when doing image.Draw() I get 'debug assertion failed' inside ReleaseDc().

Re: Drawing pictures c++ win32

David Crow18-Mar-08 3:25

David Crow

18-Mar-08 3:25

Hanan888 wrote:
...I get 'debug assertion failed' inside ReleaseDc().

What line of what file is asserting?

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: Drawing pictures c++ win32

Hanan88818-Mar-08 3:33

Hanan888

18-Mar-08 3:33

in <atlimage.h>, line 1217

inline void CImage::ReleaseDC() const throw()
{
	HBITMAP hBitmap;

	ATLASSUME( m_hDC != NULL );

	m_nDCRefCount--;
	if( m_nDCRefCount == 0 )
	{
		hBitmap = HBITMAP( ::SelectObject( m_hDC, m_hOldBitmap ) );
		ATLASSERT( hBitmap == m_hBitmap );
		s_cache.ReleaseDC( m_hDC );
		m_hDC = NULL;
	}
}

Re: Drawing pictures c++ win32

Mark Salsbery18-Mar-08 7:06

Mark Salsbery

18-Mar-08 7:06

Can you show the code?

What are you calling ReleaseDC() on? The CImage object?

You shouldn't be using CImage::GetDC()/CImage::ReleaseDC() when
using CImage::Draw().

Mark

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

char * to TCHAR

Royaltvk18-Mar-08 1:40

Royaltvk

18-Mar-08 1:40

I have a function like this

BOOL CShowAndEditSQLDlg::IsSQLKeyword( CString strSQLWord )<br />
{<br />
<br />
char * strKeyword[19] = { "SELECT", "FROM", "WHERE", "IN", "ORDER", "GROUP", "BY", <br />
		                                   "INNER", "OUTER", "JOIN", "AS", "ON", "MIN", "MAX", "AVG", "SUM", ",", "AND", "."};<br />
<br />
	<br />
	for ( int  i =0; i < 19; i++ )<br />
		if ( stricmp ( strKeyword[i], LPCTSTR(strSQLWord) ) == 0 )<br />
			return TRUE;<br />
<br />
return FALSE;<br />
}

But if I Compile that code with UNICODE settings, it is giving following error.

error C2664: 'stricmp' : cannot convert parameter 1 from 'unsigned short *' to 'const char *'

Please help me.

CPallini18-Mar-08 1:59

18-Mar-08 1:59

Royaltvk wrote:
error C2664: 'stricmp' : cannot convert parameter 1 from 'unsigned short *' to 'const char *'

Probably the error comes instead on parameter 2.

Anyway, change your code as follows

BOOL CShowAndEditSQLDlg::IsSQLKeyword( CString strSQLWord )
{

TCHAR * strKeyword[19] = { _T("SELECT"), _T("FROM"), _T("WHERE"), _T("IN"), _T("ORDER"), _T("GROUP"), _T("BY"),
_T("INNER"), _T("OUTER"), _T("JOIN"), _T("AS"), _T("ON"), _T("MIN"), _T("MAX"), _T("AVG"), _T("SUM"), _T(","), _T("AND"), _T(".")};


for ( int i =0; i < 19; i++ )
if ( _tcsicmp ( strKeyword[i], LPCTSTR(strSQLWord) ) == 0 )
return TRUE;

return FALSE;
}

OT: sorry Mark no GetBuffer here. Big Grin | :-D

Royaltvk18-Mar-08 2:17

Royaltvk

18-Mar-08 2:17

Thank u somuch for your code
It is perfectly working.

U got my 5 Marks.

Royal.

CPallini18-Mar-08 3:06

18-Mar-08 3:06

Actually I got 1, anyway, you're welcome.
Smile | :)

Rajesh R Subramanian18-Mar-08 4:11

Rajesh R Subramanian

18-Mar-08 4:11

I've balanced it up with my 5 vote. Smile | :)

Nobody can give you wiser advice than yourself. - Cicero
.·´¯`·->Rajesh<-·´¯`·.
Codeproject.com: Visual C++ MVP

CPallini18-Mar-08 4:51

18-Mar-08 4:51

Ah, were you, thanks buddy!
Smile | :)

Mark Salsbery18-Mar-08 7:09

Mark Salsbery

18-Mar-08 7:09

CPallini wrote:
OT: sorry Mark no GetBuffer here.

Hehe I can't believe that caught my eye when I glazed over your post Poke tongue | ;-P

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

Cedric Moonen18-Mar-08 2:14

Cedric Moonen

18-Mar-08 2:14

To complete with the previous answer, you can also have a look at this article[^] if you want to understand a bit better why you have that compilation error.

Cédric Moonen
Software developer

Charting control [v1.3]

Re: toolbar on a dialog box

David Crow18-Mar-08 3:36

David Crow

18-Mar-08 3:36

Is IsSQLKeyword() called often?

[Message Deleted]

preeti sharma18-Mar-08 0:30

preeti sharma

18-Mar-08 0:30

[Message Deleted]

Rajesh R Subramanian18-Mar-08 1:11

Rajesh R Subramanian

18-Mar-08 1:11

preeti sharma wrote:
how can i create a toolbar on a dialog box in MFC.

By performing a basic google search[^]

Nobody can give you wiser advice than yourself. - Cicero
.·´¯`·->Rajesh<-·´¯`·.
Codeproject.com: Visual C++ MVP

hourglass cursor not showing in thread

josip cagalj18-Mar-08 0:27

josip cagalj

18-Mar-08 0:27

Hi to all!
In my code I call 'AfxBeginThread' in which I fetch data from Database. I use 'theApp.DoWaitCuscor(1)' within thread to display hourglass cursor and 'theApp.DoWaitCuscor(-1)' to remove it when I'm done.
But this don't happens. Why?
P.S.
Thanks for all help

CPallini18-Mar-08 0:46

18-Mar-08 0:46

Don't do that inside the worker thread. Post a message from the worker thread to the GUI one and let the latter do the job.
Smile | :)

josip cagalj18-Mar-08 5:23

josip cagalj

18-Mar-08 5:23

Thanks for help, I post two messages one at the beginning of thread and one when all the work is done. My 'PreTranslateMessage' loks like this:

BOOL CUsageAccView::PreTranslateMessage(MSG* pMsg) <br />
{<br />
	if(pMsg->message == WMU_WORK_START)<br />
	{<br />
		//AfxMessageBox("Start");<br />
		::SetCursor(LoadCursor(NULL,IDC_WAIT));<br />
	}<br />
	else if(pMsg->message == WMU_WORK_END)<br />
	{<br />
		//AfxMessageBox("End");<br />
		::SetCursor(LoadCursor(NULL,IDC_ARROW));<br />
	}<br />
	return cdxCDynamicFormView::PreTranslateMessage(pMsg);<br />
}<br />

This works fine if I don't move mouse, but when I do cursor restores it self!
Why?

CPallini18-Mar-08 5:31

Re: hourglass cursor not showing in thread [modified]

18-Mar-08 5:31

From MSDN, SetCursor reference

If your application must set the cursor while it is in a window, make sure the class cursor for the specified window's class is set to NULL. If the class cursor is not NULL, the system restores the class cursor each time the mouse is moved.

you may also change the class cursor of your window:

SetClassLong( hWnd, GCL_HCURSOR, (LONG)LoadCursor(NULL, IDC_ARROW));

josip cagalj18-Mar-08 5:50

josip cagalj

18-Mar-08 5:50

Another thanks man!
Where do you suppose I include this line of code, in 'OnInitialUpdate' of my view?
Thanks.
P.S.
I included this line:
SetClassLong( this->m_hWnd, GCL_HCURSOR, (LONG)LoadCursor(NULL, IDC_ARROW));
at my view-s OnInitialUpdata and still no change, my cursor still reset from hourglass to arrow when I move the mouse!

modified on Tuesday, March 18, 2008 12:08 PM

CPallini18-Mar-08 6:46