PopupMenu from MenuBar when right click - c++

Question

Here is the piece of code that gives me a problem :
void CMainFrame::DisplayActionsPopupMenu()
{
// get "Actions" menu
wxMenuBar* pMenuBar = GetMenuBar();
ASSERT(pMenuBar != NULL);
int nIndex = pMenuBar->FindMenu("Actions");
ASSERT(nIndex != wxNOT_FOUND);
wxMenu *pMenuActions = pMenuBar->GetMenu(nIndex);
ASSERT(pMenuActions != NULL);
// display a popup menu for actions
PopupMenu(pMenuActions);
}
What I try to do here is to display a popupmenu when right clicking and I want it to be the same as the second menu in the menubar of my project.
It worked when I compiled with wxWidgets v2.8
Now I tried with v3.0 and here is the error:
../src/common/menucmn.cpp(715): assert "!IsAttached()" failed in SetInvokingWindow(): menus attached to menu bar can't have invoking window
What should I do to fix this?

Answer 1

I think a more robust solution than the existing answer consisting in detaching and attaching back the menu would be to just create a new menu instead, e.g. something like this:
std::unique_ptr<wxMenu> CreateActionsMenu() { ... }
// In your frame ctor or wherever you initialize your menu bar.
MyFrame::MyFrame() {
wxMenuBar* const mb = new wxMenuBar;
mb->Append(CreateActionsMenu().release(), "&Actions");
SetMenuBar(mb);
}
// In your event handler function showing the popup menu.
void MyFrame::OnShowPopup(wxCommandEvent&) {
auto menu = CreateActionsMenu();
PopupMenu(menu.get());
}
Creating a menu is relatively fast and there should be no problem doing it just before showing it (although, of course, you could also cache it for later if it's really huge or otherwise expensive to construct).

Answer 2

Finally I found that with the >3.0 wxWidgets version, you can't get elements from the wxMenuBar which is attached to your frame. So you have to temporarly unattach and reattach it.
Here is how you would so:
1 - Initialize the new wxMenu with the MenuBar. In my case:
wxMenuBar* pMenuBar = GetMenuBar();
ASSERT(pMenuBar != NULL);
cout<<pMenuBar->IsAttached()<<endl;
int nIndex = pMenuBar->FindMenu("Actions");
ASSERT(nIndex != wxNOT_FOUND);
wxMenu *pMenuActions = pMenuBar->GetMenu(nIndex);
2 - Check if it's attached:
if(pMenuActions->IsAttached()){
pMenuActions->Detach();
}
3 - When your done, reAttach the wxMenu to the wxMenuBar
pMenuActions->Attach(pMenuBar);