C / C++ / MFC

UINT16 TransmitData( UINT unit, UINT addr, TXBUFFER * tx_buffer );

CBand::CBand()
{	
	//ALWAYS SHOWS
	MessageBox(0, "Construct", 0,0)  ;
	m_lRef			= 1 ;
	//create obejcts...
}
CBand::~CBand()
{
	//NEVER SHOWN
	MessageBox(0, "Destruct", 0,0)  ;
	//delete objects
}

DWORD	__stdcall CBand::AddRef()
{
	return InterlockedIncrement(&m_lRef) ;
}
DWORD	__stdcall CBand::Release()
{
	if( InterlockedDecrement(&m_lRef) == 0 )
	{
		delete this ;
	}
	return m_lRef ;
}
HRESULT __stdcall CBand::QueryInterface( REFIID riid , void** ppvObj )
{
	*ppvObj = NULL;

	if(IsEqualIID(riid, IID_IUnknown))
	{
		*ppvObj = this;
	}
	.
	.
	.
	.

	if(*ppvObj)
	{
		(*(LPUNKNOWN*)ppvObj)->AddRef();
		return S_OK;
	}

	return E_NOINTERFACE;
}

HRESULT __stdcall ShellFactory::CreateInstance(IUnknown* pUnknownOuter , const IID& iid , void** ppv ) 
{    
	if( pUnknownOuter != NULL )
	{
        return ResultFromScode( CLASS_E_NOAGGREGATION ) ;
	}

	if( IsEqualCLSID(m_clsid , CLSID_MyBand))
	{
		CBand * pObj = new CBand() ;
		if( pObj == NULL )
		{
			return E_OUTOFMEMORY;
		}
		HRESULT hRes = pObj->QueryInterface( iid , ppv ) ;	
		if(FAILED(hRes) )
		{
			pObj->Release() ;
		}
		return hRes;
	}
	return S_FALSE ;
}

// Dialog1 Class
class Dialog1 : public CDialog
{
public:
	void CallCopyFnc();
private:
	Dialog2* myDlg2;
}


// Dialog2 Class that has Child property set
class Dialog2 : public CDialog
{
public:
	void CopyDataFnc();
}


// In Dialog1 cpp file
Dialog1::OnInitData()
{
	myDlg2 = new Dialog2;
}

Dialog1::CalllCopyFnc()
{
	myDlg2->CopyDataFnc();
}


// In Dialog2 cpp file
Dialog2::CopyDataFnc()
{
	CString str;

	str.Format("0x%08X", number);
	EditCtrl.SetDlgItemTextA(idEditCtrl, str);
	// This does nothing to the Edit control and I can not read the 
	// text in it either if I use GetDlgItemText()
	// If I use Get or SetDlgItemText(idEditctrl, str); then I get an unhandled exception - 
}