C / C++ / MFC

class CMFCPropertyGridCtrl 
{
	friend class CMFCPropertyGridColorProperty;

protected:
	CRect m_rectList; // Properies area
};

class CMFCPropertyGridColorProperty
{
	friend class CMFCPropertyGridCtrl;

public:
	virtual void AdjustInPlaceEditRect(CRect& rectEdit, CRect& rectSpin);

protected:
	// back pointer
	CMFCPropertyGridCtrl* m_pWndList;
};

void CMFCPropertyGridColorProperty::AdjustInPlaceEditRect(CRect& rectEdit, CRect& rectSpin)
{
	// original code removed for clarity.

	// access to CMFCPropertyGridCtrl::m_rectList;
	m_pWndList->m_rectList.left += 20;
}

class MyPropertyGrid : public CMFCPropertyGridColorProperty 
{
	virtual void AdjustInPlaceEditRect(CRect& rectEdit, CRect& rectSpin);
};

void MyPropertyGrid::AdjustInPlaceEditRect(CRect& rectEdit, CRect& rectSpin)
{
	// original code removed for clarity.
	// access to CMFCPropertyGridCtrl::m_rectList;
	m_pWndList->m_rectList.left += 40;  // ERROR.
}

virtual void AdjustInPlaceEditRect(CRect& rectEdit, CRect& rectSpin);

void CMFCPropertyGridColorProperty::AdjustInPlaceEditRect(CRect& rectEdit, CRect& rectSpin)
{
	ASSERT_VALID(this);
	ASSERT_VALID(m_pWndList);

	rectSpin.SetRectEmpty();

	rectEdit = m_Rect;
	rectEdit.DeflateRect(0, 2);

	int nMargin = m_pWndList->m_bMarkModifiedProperties && m_bIsModified ? m_pWndList->m_nBoldEditLeftMargin : m_pWndList->m_nEditLeftMargin;

	rectEdit.left = m_pWndList->m_rectList.left + m_pWndList->m_nLeftColumnWidth + m_Rect.Height() + AFX_TEXT_MARGIN - nMargin + 1;

	AdjustButtonRect();
	rectEdit.right = m_rectButton.left;
}

CFile* pFile = new CFile;
pFile->Open("Output.pcm", CFile::modeCreate|modeReadWrite);
pFile->Write((void*)pData, dwLength); // exception raised here
pFile->Close();