How to Enable Edit Menu Commands for Edit Controls

• The Microsoft Foundation Classes (MFC), included with:
  • Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52
  • Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 2.2, 4.0

SUMMARY

On a CDialog or other window that has no edit menu options for cutting, copying, and pasting, CEdit controls handle these functions through the normal Windows accelerator processing (CTRL+X,V,C, or the SHIFT-DELETE, SHIFT-INSERT, CTRL-INSERT, CTRL-DELETE, and so on keys). However, in a typical MDI or SDI application, these options are disabled.

This is due to the default implementation for menu handlers and accelerator keys that AppWizard adds to your application to handle these functions. These menu handlers get the accelerator keystrokes instead of your edit control. This article shows you how to implement the edit control's clipboard functions on a CFormView-derived form.

MORE INFORMATION

If you completely remove the menu options (not just enable or disable) and any accelerator definitions for the standard edit accelerator keys, then there will be no conflict and your CEdit controls will take care of their clipboard functions as usual. However, if you want to implement the common Edit menu clipboard functions (and toolbar Edit buttons), you will have to add some additional handlers to your program.

• Your UPDATE_COMMAND_UI handlers will need to determine if the control with the focus is really a CEdit and if there is any text available for the operation.



• Because you have menu items for Cut, Copy, or Paste that are tied to the standard accelerators, you need to write handlers for the actions.

Step-by-Step Example

1. First, determine if it is a CEdit control that has the focus:

   
      // IsEdit: a helper function to determine if a given CWnd pointer
      // points to a CEDit control.
      // Use the SDK ::GetClassName() function because MFC IsKindOf
      // fails if no CEdit variable has been created for the control you're
      // trying to test.
   
      BOOL CMyFormView::IsEdit( CWnd* pWnd )
      {
         ASSERT( pWnd != NULL );
         HWND hWnd = pWnd->GetSafeHwnd();
         if (hWnd == NULL)
            return FALSE;
   
         TCHAR szClassName[6];
         return ::GetClassName(hWnd, szClassName, 6) &&
                _tcsicmp(szClassName, _T("Edit")) == 0;
      } 




2. Add an UPDATE_COMMAND_UI handler for ID_EDIT_COPY & ID_EDIT_CUT:

   
      // UPDATE_COMMAND_UI handler for Edit Copy and Edit Cut which both
      // require that the current focus is on an edit control that has
      // text selected.
   
      void CMyFormView::OnUpdateNeedSel(CCmdUI* pCmdUI)
      {
        // get the current focus & determine if its on a CEdit control
         CWnd* pWnd = GetFocus();
         if (NULL == pWnd || !IsEdit( pWnd ))
         {
            pCmdUI->Enable( FALSE );
         }
         else
         {
            CEdit* pEdit = (CEdit*)pWnd;
            int nBeg, nEnd;
   
            pEdit->GetSel( nBeg, nEnd );
            pCmdUI->Enable( nBeg != nEnd );
         }
      } 




3. Add UPDATE_COMMAND_UI handlers for ID_EDIT_PASTE:

   
      // UPDATE_COMMAND_UI handlers for Edit Paste requires that focus be
      // on an edit control and that the clipboard contains text to be
      // pasted into the control.
   
      void CMyFormView::OnUpdateNeedClip(CCmdUI* pCmdUI)
      {
         // get the current focus & determine if its on a CEdit control
         // also check to see if the control is read-only.
         CWnd* pWnd = GetFocus();
         if (  NULL == pWnd ||
               !IsEdit( pWnd ) ||
               (pWnd->GetStyle() & ES_READONLY) != 0 )
         {
            pCmdUI->Enable( FALSE );
         }
         else
            pCmdUI->Enable(::IsClipboardFormatAvailable(CF_TEXT));
      } 




4. Add standard handlers for ID_EDIT_COPY, ID_EDIT_CUT, and ID_EDIT_PASTE:

   
      void CMyFormView::OnEditCopy()
      {
         CEdit* pEdit = (CEdit*)GetFocus();
         ASSERT( IsEdit( pEdit) );
         pEdit->Copy();
      }
   
      void CMyFormView::OnEditCut()
      {
         CEdit* pEdit = (CEdit*)GetFocus();
         ASSERT( IsEdit( pEdit) );
         pEdit->Cut();
      }
   
      void CMyFormView::OnEditPaste()
      {
         CEdit* pEdit = (CEdit*)GetFocus();
         ASSERT( IsEdit( pEdit) );
         ASSERT(::IsClipboardFormatAvailable(CF_TEXT));
         pEdit->Paste();
      } 

Additional query words: kbinf 1.00 1.50 2.50 2.51 2.52 2.00 2.10 2.20 3.00 3.10 3.20 4.00

Keywords : kbcode kbMFC KbUIDesign kbVC
Version : 1.00 1.50 1.51 1.52 | 2.00 2.10
Platform : NT WINDOWS
Issue type :