C / C++ / MFC

// MessageId: ERROR_BAD_PATHNAME
//
// MessageText:
//
//  The specified path is invalid.
//
#define ERROR_BAD_PATHNAME               161L

CRegKey autoRunKey;
long ret;

if ((ret = autoRunKey.Create(HKEY_CURRENT_USER, "\\Software\\Microsoft\\Windows\\CurrentVersion\\Run")) != ERROR_SUCCESS)
{
    CString f;
    f.Format("Couldn't open key.. return code is %ld", ret);

    AfxMessageBox(f);
}

ON_NOTIFY_REFLECT(HDN_DIVIDERDBLCLICK, OnDividerdblclick)

ON_NOTIFY(HDN_DIVIDERDBLCLICK, 0, OnDividerdblclick)

BOOL CNumbersListCtrl::OnNotify(WPARAM wParam, LPARAM lParam, LRESULT* pResult) 
{
    NMHDR* pNMHDR = (NMHDR*)lParam;  	// Trap Header control notifications here 
	
    HD_NOTIFY *phdn = (HD_NOTIFY *)lParam; 
    switch(phdn->hdr.code)
 	{ 		
        case HDN_BEGINTRACK:
        {
            // Trap the HDN_BEGINTRACK message
            TRACE(_T("CNumbersListCtrl::OnNotify -- HDN_BEGINTRACK Trapped\n"));
            return(FALSE);  // return FALSE to allow tracking of the divider 
            break; 		
        }
        case HDN_ENDTRACK:
	{
            TRACE(_T("CNumbersListCtrl::OnNotify -- HDN_ENDTRACK Trapped\n"));
            if (phdn->iItem == 0)
	    {
                TRACE(_T("CNumbersListCtrl::OnNotify -- Resising right to fit\n"));
            }
            else if (phdn->iItem == 1)
	    {
                TRACE(_T("CNumbersListCtrl::OnNotify -- Resising left to fit\n"));
            }	
            break;
	}
    }	 	
    return CListCtrl::OnNotify(wParam, lParam, pResult); 

}

BOOL CNumbersListCtrl::OnNotify(WPARAM wParam, LPARAM lParam, LRESULT* pResult) 
{
    HD_NOTIFY *phdn = (HD_NOTIFY *)lParam; 
    switch(phdn->hdr.code)
    { 		
        case HDN_BEGINTRACKA:
        case HDN_BEGINTRACKW:
        {
            // Trap the HDN_BEGINTRACK message
            TRACE(_T("CNumbersListCtrl::OnNotify -- HDN_BEGINTRACK Trapped\n"));
            SetRedraw(false);
            // *pResult = 1;  // Set to 1 and return TRUE to prevent tracking 
            return(FALSE);  // return FALSE to allow tracking of the divider 
            break; 		
        }
        case HDN_ENDTRACKA:
        case HDN_ENDTRACKW:
        {
            int windowsize = 225;   
            TRACE(_T("CNumbersListCtrl::OnNotify -- HDN_ENDTRACK Trapped\n"));

            SCROLLINFO si; // check if scrollbar is visible
            if (GetScrollInfo(SB_VERT, &si))
            {
                if ((int) si.nPage <= (si.nMax-si.nMin))
                    windowsize = 225;
                else
                    windowsize = 240;
            }
            else
                windowsize = 240;
			
            if (phdn->iItem == 0)
	    {
                int left = phdn->pitem->cxy;
                TRACE(_T("CNumbersListCtrl::OnNotify -- Resize right to fit\n"));
                SetColumnWidth(1, windowsize - left);
            }
            else if (phdn->iItem == 1)
            {
                int right = phdn->pitem->cxy;
                TRACE(_T("CNumbersListCtrl::OnNotify -- Resize left to fit\n"));
                SetColumnWidth(0, windowsize - right);
            }	
            SetRedraw(true);
            Invalidate();
            break;
        }
    }	 	
    return CListCtrl::OnNotify(wParam, lParam, pResult); 

}

BEGIN_MESSAGE_MAP(CMyHeaderCtrl, CHeaderCtrl)
	//{{AFX_MSG_MAP(CMyHeaderCtrl)
	ON_NOTIFY_REFLECT(HDN_BEGINTRACKA, OnHdnBegintrack)
	ON_NOTIFY_REFLECT(HDN_BEGINTRACKW, OnHdnBegintrack)
	ON_NOTIFY_REFLECT(HDN_ENDTRACKA, OnHdnEndtrack)
	ON_NOTIFY_REFLECT(HDN_ENDTRACKW, OnHdnEndtrack)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CMyHeaderCtrl message handlers
void CMyHeaderCtrl::OnHdnBegintrack(NMHDR *pNMHDR, LRESULT *pResult)
{
	LPNMHEADER phdr = reinterpret_cast<LPNMHEADER>(pNMHDR);
	// TODO: Add your control notification handler code here
	*pResult = 0;
}


void CMyHeaderCtrl::OnHdnEndtrack(NMHDR *pNMHDR, LRESULT *pResult)
{
	LPNMHEADER phdr = reinterpret_cast<LPNMHEADER>(pNMHDR);
	// TODO: Add your control notification handler code here
	*pResult = 0;
}

CDlg::OnInitDialog()
{       ...
        m_MyListCtrl.InsertColumn(0, "First");
	m_MyListCtrl.InsertColumn(1, "Second");
	CHeaderCtrl* pHeaderCtrl = m_MyListCtrl.GetHeaderCtrl();
        ASSERT_VALID(pHeaderCtrl);
        if(pHeaderCtrl && pHeaderCtrl->GetSafeHwnd())
	     VERIFY(m_MyHeaderCtrl.SubclassWindow(pHeaderCtrl->m_hWnd));
        ...
}

void CMyHeaderCtrl::OnHdnBegintrack(NMHDR *pNMHDR, LRESULT *pResult)
{
	LPNMHEADER phdr = reinterpret_cast< LPNMHEADER >(pNMHDR);
	// TODO: Add your control notification handler code here
	*pResult = 0;
}


void CMyHeaderCtrl::OnHdnEndtrack(NMHDR *pNMHDR, LRESULT *pResult)
{
	LPNMHEADER phdr = reinterpret_cast < LPNMHEADER > (pNMHDR);
	// TODO: Add your control notification handler code here
	*pResult = 0;
}