PRB: Pop-Up Menu Items Disabled for an OLE Control

• Microsoft Visual C++, 32-bit Edition, version 4.0, 4.1, 4.2, 5.0

SYMPTOMS

The menu items are disabled even though menu handlers were added with Class Wizard when you create an OLE Control and then use the Pop-up Menu component in the Component Gallery to add a context menu to the COleControl derived class. The problem occurs after you modify the context menu, and then add handlers for the menu items, build the Control, place it in Tstcon32.exe, and bring up the context menu.

CAUSE

Within the OnContextMenu function added by the Pop-up Menu Component, the code makes the top-most parent window the parent of the context menu. The menu sends the WM_COMMAND message to its parent first, which can then route the command appropriately through the application. This method works for windows in an MFC application that are part of the command-routing scheme. However, because OLE Controls are not part of the routing mechanism, the WM_COMMAND message never gets back to them and therefore the context menu doesn't see the handlers, so the menu items are disabled.

RESOLUTION

When you add a context menu to an OLE control, you need to make the COleControl derived class the parent of the context menu. The Pop-up Menu Component creates the following code within the CWnd derived class. If the pop-up menu is being added to a COleControl-derived class, you need to delete the following lines of code:

   while (pWndPopupOwner->GetStyle() & WS_CHILD)
      pWndPopupOwner = pWndPopupOwner->GetParent();

Code Created by Pop-up Menu Component

   void CSPLITCtrl::OnContextMenu(CWnd*, CPoint point)
   {
      // CG: This function was added by the Pop-up Menu component

      CMenu menu;
      VERIFY(menu.LoadMenu(CG_IDR_POPUP_SPLITCTRL));

      CMenu* pPopup = menu.GetSubMenu(0);
      ASSERT(pPopup != NULL);

      CWnd* pWndPopupOwner = this;
      while (pWndPopupOwner->GetStyle() & WS_CHILD)
         pWndPopupOwner = pWndPopupOwner->GetParent();

      pPopup->TrackPopupMenu(TPM_LEFTALIGN | TPM_RIGHTBUTTON, point.x,
                             point.y, pWndPopupOwner);
   }