PRB: TranslateAccelerator() Not Called for ActiveX Controls

• The Microsoft Foundation Classes (MFC), included with:
  • Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1, 4.2, 5.0, 6.0

SYMPTOMS

An ActiveX control can process keyboard messages in the IOleInPlaceActiveObject::TranslateAccelerator() function. If the ActiveX control is created dynamically in a CView class or a CPropertyPage class, TranslateAccelerator() will not be called.

CAUSE

The CView and CPropertyPage classes are not designed to host ActiveX controls, therefore they do not call the TranslateAccelerator() function.

RESOLUTION

Override the PreTranslateMessage() function and call the PreTranslateInput() function. This results in a call to the COccManager::IsDialogMessage() function, which calls the control's IOleInPlaceActiveObject::TranslateAccelerator() function.

The following sample code shows how to override PreTranslateMessage() in a CView-derived class called CTestView:

Sample Code

   BOOL CTestView::PreTranslateMessage(MSG* pMsg)
   {
      CView::PreTranslateMessage(pMsg);
      return PreTranslateInput (pMsg);
   } 

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

1. Create an ActiveX control project with the MFC ActiveX ControlWizard.



2. In the WM_CREATE message handler, create two edit controls as child windows of the ActiveX control, as in the following example:

   
         // CEditOCXCtrl is a COleControl-derived class.
         int CEditOCXCtrl::OnCreate(LPCREATESTRUCT lpCreateStruct)
         {
            if (COleControl::OnCreate(lpCreateStruct) == -1)
               return -1;
   
            // m_Edit1 and m_Edit2 are of type CEdit.
            VERIFY(m_Edit1.Create(WS_CHILD | WS_VISIBLE | WS_TABSTOP |
                                  WS_BORDER,
               CRect(10, 10, 100, 40), this, 100));
            VERIFY(m_Edit2.Create(WS_CHILD | WS_VISIBLE | WS_TABSTOP |
                                  WS_BORDER,
               CRect(10, 50, 100, 80), this, 101));
            return 0;
         } 




3. Override PreTranslateMessage() in the COleControl-derived class as follows:

   
         BOOL CEditOCXCtrl::PreTranslateMessage(MSG* pMsg)
         {
            if (pMsg->message >= WM_KEYFIRST && pMsg->message <= WM_KEYLAST)
            {
               // Allow tabbing between child controls.
               if (VK_TAB == pMsg->wParam)
               {
                  if (IsDialogMessage(pMsg))
                     return TRUE;
               }
            }
   
            return COleControl::PreTranslateMessage(pMsg);
         } 




4. Create an SDI application with CView as its view class in AppWizard.



5. Insert the ActiveX control's CWnd-wrapper class to the SDI project in Component Gallery.



6. Create the ActiveX control dynamically in the OnInitialUpdate() function of the CView-derived class:

   
         // CSdiView is a CView-derived class.
         void CSdiView::OnInitialUpdate()
         {
            CView::OnInitialUpdate();
   
            m_pSelection = NULL;    // Initialize selection.
   
            // m_EditOCX is the CWnd-wrapper class of the ActiveX control.
            VERIFY(m_EditOCX.Create("", WS_CHILD | WS_VISIBLE | WS_TABSTOP,
               CRect(10, 10, 200, 200), this, 555));
         } 




7. Build the SDI project and run the SDI application. Type something in the edit control of the ActiveX control. Note that the PreTranslateMessage() of the ActiveX control is not called.

Additional query words: ocx kbvc400 kbvc410 kbvc420 kbvc500 kbvc600

Keywords : kbole kbMFC kbVC
Version : winnt:4.0,4.1,4.2,5.0,6.0
Platform : winnt
Issue type : kbprb