C / C++ / MFC

Re: is multiple inheritance possible??

16-Nov-04 3:48

i wanted to derive a class that has the properties of both the CDialog and CStatic class but when i use the wizard to make a new class they give the provision only for one base class??

is it possible to have more than one base class ??if so.....how is it done??

thanx!!!!!

Nemanja Trifunovic16-Nov-04 4:01

Nemanja Trifunovic

16-Nov-04 4:01

I am not sure it is a good idea. Both CDialog and CStatic are derived from CWnd, and you would get a diamond of death[^] (unless CWnd is a virtual base, but I doubt it is Unsure | :~

)

My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.

Re: is multiple inheritance possible??

David Crow16-Nov-04 4:07

David Crow

16-Nov-04 4:07

Not that I condone it, but can you use ClassWizard to derive your class from CDialog, and then manually add CStatic to the base list in the class' .h file?

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

Re: is multiple inheritance possible??

Maximilien16-Nov-04 4:31

Maximilien

16-Nov-04 4:31

what property does CStatic contains that can be usefull for a CDialog ?

Confused | :confused:

Maximilien Lincourt
Your Head A Splode - Strong Bad

how do i change the color of the frame of a picture control???

namaskaaram16-Nov-04 3:45

regarding mouse events.....

16-Nov-04 3:45

Dear friendz....

i would like to know how i can change the color of the frame of a picture control placed on a dialog box when a certain event(say onmousemove())takes place??

all suggestionz are welcome.....

thanx in advance...

namaskaaram16-Nov-04 3:43

16-Nov-04 3:43

plz help!!!!! Cry | :((

HICON hIcon = AfxGetApp()->LoadCursor( IDC_CURSOR1 );
SetCursor( hIcon );
return TRUE;

is a working code coz i have put this in my Dialog based application (Xyz) in a class called CXyzDlg..... that is, i have already added this function "OnSetCursor()".....and the cursor changes......in the main Dlg box but..... i have derived a class from the CStatic Class named it as "CMyClass".....and i have created obcts of it in the CXyzDlg class.....basically these objects i have created by placing the "static control" on the dialog box and then..... thru the class wizard created an object linking it with the picture control of type CMyClass(that is .....SUBCLASSING).....
also in thiz CMyClass i have added the "OnSetCursor()" function as well......and many other mouse functions like "onmousemove()","LbuttonDown()".....etc.....but here when i put in the same code as i had put in the main Dlg box for the "OnsetCursor()".....it does not change!!!!!......y???

heres the code......that i have put in the derived class CMyClass......

// MyClass.cpp : implementation file
//

#include "stdafx.h"
#include "creamz.h"
#include "MyClass.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CMyStaticpot1

CMyClass::CMyClass()
{
m_DragOn1=FALSE;
m_pot1=0;
m_update=TRUE;
//AfxMessageBox("constructor activated");
}

CMyClass::~CMyClass()
{
}


BEGIN_MESSAGE_MAP(CMyClass, CStatic)
//{{AFX_MSG_MAP(CMyStaticpot1)
ON_WM_LBUTTONDOWN()
ON_WM_LBUTTONUP()
ON_WM_MOUSEMOVE()
ON_WM_SETCURSOR()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CMyClass message handlers

void CMyClass::OnLButtonDown(UINT nFlags, CPoint point) 
{
// TODO: Add your message handler code here and/or call default

HICON hIcon = AfxGetApp()->LoadCursor( IDC_CURSOR2 );
SetCursor( hIcon );
m_DragOn1=TRUE;


CStatic::OnLButtonDown(nFlags, point);
}

void CMyClass::OnLButtonUp(UINT nFlags, CPoint point) 
{
// TODO: Add your message handler code here and/or call default
//AfxMessageBox("click up");

HICON hIcon = AfxGetApp()->LoadCursor( IDC_CURSOR1 );
SetCursor( hIcon );
m_DragOn1=FALSE;


CStatic::OnLButtonUp(nFlags, point);
}

void CMyClass::onmousemove(UINT nFlags, CPoint point) 
{
// TODO: Add your message handler code here and/or call default

//AfxMessageBox("move");

if(m_DragOn1==TRUE)
{

if(m_pot1<62)
m_pot1+=1;
else
m_pot1=0;

//AfxMessageBox("dragging");
// Invalidate();
if(m_pot1%2==0)
m_update=TRUE;

}//end of if(m_DragOn==TRUE)




CStatic::onmousemove(nFlags, point);
}

BOOL CMyClass::OnSetCursor(CWnd* pWnd, UINT nHitTest, UINT message) 
{
// TODO: Add your message handler code here and/or call default

if(m_DragOn1==FALSE)
{

//AfxMessageBox("CURSOR SET");

HICON hIcon = AfxGetApp()->LoadCursor( IDC_CURSOR1 );
SetCursor( hIcon );
}
else
{
HICON hIcon = AfxGetApp()->LoadCursor( IDC_CURSOR2 );
SetCursor( hIcon );
} 


return TRUE;


// return CStatic::OnSetCursor(pWnd, nHitTest, message);
}

plz help me out......
thanx in advance.....and thanx for ur intrest!!!!!

Blake Miller16-Nov-04 4:43

16-Nov-04 4:43

I think your problem maybe use of local variable that goes out of scope immediately after your call to SetCursor.

I suggest making a member variable for your class:
HICON m_CursorIcon;

In your constructor, set it to NULL:
m_CursorIcon = (HICON)0;

Add a new member function you call anytime you want to change the cursor:

void MySetCursor(UINT idCursor){<br />
// try to load new cursor<br />
m_CursorIcon = AfxGetApp()->LoadCursor( idCursor );<br />
// do nothing if not loaded<br />
if( !m_CursorIcon ){<br />
 // you might want to TRACE something out here or assert<br />
 return;<br />
}<br />
// set new cursor<br />
SetCursor( m_CursorIcon );<br />
}

namaskaaram16-Nov-04 17:52

16-Nov-04 17:52

thanx for the reply.....but that too doesnt work..... Sigh | :sigh:

.....i dont think m_cursorIcon being a local variable is a prob actually coz i had put in a code to trace if the control was going to the OnSetCursor() and it does.....only thing is that the mouse pointer doesnt get updated......
any ideas??? Confused | :confused:

thanx a lot for ur reply..... Big Grin | :-D

Blake Miller17-Nov-04 4:05

17-Nov-04 4:05

Here is an idea, from the MSDN:
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.

namaskaaram17-Nov-04 18:50

17-Nov-04 18:50

can u elaborate a little more please!!!!!.....what am i to make NULL??is it the OnSetCursor

Blake Miller18-Nov-04 4:04

CoTaskMemAlloc and BITMAPINFO

18-Nov-04 4:04

It involves checking and possibly changing the HCURSOR field of the WNDCLASS associated with your CStatic window. However, in the context of MFC, this can get you into trouble really quick, since you would be changing it for EVERY CStatic in the program - and every window using the class registered (which cna be other types, knowing hwo MFC seems ot work...).

As a different approach, why don't you look at Chris' CHyperLink control on this website. Study his code, because, as I recall, it changes the cursor to a pointy hand when the mouse is over the window. Using his code as an exmaple, you should be able to see how to get the cursor changed in your window. I think his is even derived from CStatic.

http://www.codeproject.com/miscctrl/hyperlink.asp

dmxdmxdmx0516-Nov-04 3:39

dmxdmxdmx05

16-Nov-04 3:39

Is there a minimum size when allocating memory using CoTaskMemAlloc() ?
For ex;

LPBITMAPINFO pDibImage = NULL;
pDibImage = (LPBITMAPINFO)CoTaskMemAlloc(400);

once I do this, the BIMAPINFO fileds such as bmiHeader and bmiColor values
are not set to 0. They are filled with Garabage...
Why ?

but if I assign a larger memory block like..

pDibImage = (LPBITMAPINFO)CoTaskMemAlloc(6606760);

Then everything is initlized properly....

any ideas? thoughts?

Thanks

Re: CoTaskMemAlloc and BITMAPINFO

Blake Miller16-Nov-04 4:49