Windows Menus and the WM_MENUCOMMAND message

[Martin0815]

Hello, I'm working with/on an application with a resource based menu. This application is more or less driven by the programming (script) language tcl and has a lot of APIs introducing C++ functionality to tcl. Now I built an API to manage (popup) menus and their menu items, to create new items with tcl script callbacks, etc. The main point in my "construct" is to use a template menu item from a template menu resource. I created a menu in the resources as template containing a menu item as template. Everything was fine until I realized, that I seemed to have no chance to differentiate between the new commands having all the same id, but different application defined data - changed via the MENUITEMINFO and the related functions Get/SetMenuItemInfo. I changed the menus after their creation to send a WM_MENUCOMMAND message instead of a WM_COMMAND message by setting the dwStyle flag MNS_NOTIFYBYPOS inside the MENUINFO structure via a call to SetMenuInfo. Now - finally to the problem and the question - why I never receive the WM_MENUCOMMAND message? I patched CMainFrame::PreTranslateMessage method to catch the WM_MENUCOMMAND message, I tried with CMainFrame::WindowProc, and by registering a ON_MESSAGE handler inside the message map, but ... nothing worked! Thanks for any reaction in advance! Best regards, Martin Lemburg

[prasad_som]

Can you provide code ? how you are creating menu, using SetMenuInfo etc. ?

Prasad Notifier using ATL | Operator new[],delete[][^]

[Martin0815]

Yes - here's some "reduced" code: 1. the creation of a popup menu:

DWORD       style       = 0;
CMenu       \*popup      = (CMenu \*) NULL;
MENUINFO    menuInfo;   // see below (1)

memset( &menuInfo, 0x0, sizeof( MENUINFO ) );   // (1)

// create the new menu object
//
popup   = new CMenu();

// create the new popup menu
//
if ( ( popup != NULL ) && ( popup->CreatePopupMenu() == TRUE ) )
{
    // initialize the menu info structure to get its dwStyle member
    //
    menuInfo.cbSize = sizeof( MENUINFO );
    menuInfo.fMask  = MIM\_STYLE;

    if ( popup->GetMenuInfo( &menuInfo ) == TRUE )
    {
        style   = menuInfo.dwStyle;

        // (re)initialize the menu info structure to change only its dwStyle member
        //
        memset( &menuInfo, 0x0, sizeof( MENUINFO ) );

        menuInfo.cbSize     = sizeof( MENUINFO );
        menuInfo.fMask      = MIM\_APPLYTOSUBMENUS | MIM\_STYLE;
        menuInfo.dwStyle    = style | MNS\_NOTIFYBYPOS;

        if ( popup->SetMenuInfo( &menuInfo ) == TRUE )
        {
            tcl\_publishResult( ip, (char \*) create\_popup\_token( popup ) );
            return TCL\_OK;
        }
    }
}

system\_error\_message( ip, "couldn't create popup menu" );

if ( popup != NULL )
{
    delete popup;
}

return TCL\_ERROR;

2. the insertion of a created popup menu:

int             itemPosition    = 0;
char            \*label          = (char \*) NULL;
CWnd            \*root           = (CWnd \*) NULL;
CMenu           \*menu           = (CMenu \*) NULL,
                \*popup          = (CMenu \*) NULL;
MENUITEMINFO    menuInfo;       // see below (1)

Menu\_if\_tcl\_MenuItem\_s\_t    \*menuItem   = (Menu\_if\_tcl\_MenuItem\_s\_t \*) NULL;

memset( &menuInfo, 0x0, sizeof( MENUITEMINFO ) );   // (1)

menuInfo.cbSize = sizeof( MENUITEMINFO );

// get the popup menu pointer and the label ...
//
// ...
//

// access the main window
//
root    = AfxGetApp()->m\_pMainWnd;
menu    = get\_owning\_menu( ip, root->GetMenu(), positionsList, itemPosition );

if ( ( menu != NULL ) &&
     ( itemPosition != -1 ) &&
     ( (UINT) itemPosition <= menu->GetMenuItemCount() ) )
{
    if ( menu->InsertMenu( itemPosition, MF\_BYPOSITION | MF\_STRING | MF\_POPUP, (UINT) popup->m\_hMenu, label ) == TRUE )

[prasad_som]

The problem , I see in your code is, you have applied MENUINFO, before inserting menu and submenus. I tried on simple SDI application, creating a pop - up menu in resource, and using SetMenuInfo . It work like charm.

Prasad Notifier using ATL | Operator new[],delete[][^]

[Martin0815]

Hello Prasad, thanks for your engagement! I changed my sources, so that ... 1. no MENUINFO action happens while creating the popup 2. the insertion is slightly changed: 2.1 menu->InsertMenu( itemPosition, ..., popup->m_hMenu, ... ) 2.2 popup = menu->GetSubMenu( itemPosition ) 2.3 requesting with popup->GetMenuInfo the MENUINFO to get the current dwStyle member => oldStyle 2.4 changing and setting with popup->SetMenuInfo the MENUINFO with dwStyle = oldStyle | MNS_NOTIFYBYPOS I have introduced the ON_MESSAGE handler for WM_MENUCOMMAND, extended the CMainFrame::WindowProc and the CMainFrame::PreTranslateMessage, but none of them gets a WM_MENUCOMMAND message. Even if a CMainFrame instance is the owner of the menu I insert my popups in, can I really be sure, that CMainFrame instance really receives the WM_MENUCOMMAND messages? Thanks again and best regards, Martin Lemburg

[prasad_som]

Hi Martin, You must be using TrackPopupMenu for invoking pop up menu, isn't it ? Now, I'll tell you ,steps I followed to got it working. 1. Create a menu in resource editor with pop-up style. 2. Use CMenu::LoadMenu to load that menu. 3. Use SetMenuInfo as described in your original post. 4. Use TrackPopupMenu , set its parent as main frame window. 5. Override DefWndProc of CMainFrame(or you can use PreTranslateMessage). 6. I can see WM_MENUCOMMAND sent when clicked this menu. May this give you some idea.

Prasad Notifier using ATL | Operator new[],delete[][^]

[Martin0815]

Ok - got it working - a bit different than you told me to, and with a lot of consequences. The current state: 1. we have a MFC application 2. our MFC application has a resource based menu, with one ON_COMMAND handler per menu item 3. I wrote a tcl API to access the MFC application menu, which allows to create new sub menus and menu items. 4. before I insert a popup menu, I switch the MFC application menu MENUINFO to MNS_NOTIFYBYPOS, so that WM_MENUCOMMAND messages are used, instead of WM_COMMAND messages 5. after inserting a popup menu, I switch the new sub menu to use WM_MENUCOMMAND messages 6. I registered a ON_MESSAGE handler for WM_MENUCOMMAND messages The consequences: 1. None of the resource based menu items, with ON_COMMAND handlers, will work anymore, because there are no WM_COMMAND messages anymore 2. every selected menu item causes the wanted WM_MENUCOMMAND message 3. every menu in the "path" of (sub)menus seem to have this MENUINFO style flag MNS_NOTIFYBYPOS, so that this model is really working. If I don't switch all containing menus of a sub menus to send WM_MENUCOMMAND messages, than the whole model won't work. The suggestion above to use TrackPopupMenu must work, if the popup menu is used all alone, but if it is used inside a "path" of cascaded menus, than this would be more problematic. 4. the whole menu system of ON_COMMAND handlers must be rewritten, or I must find a way to get rid of the dummy or template menu item and create resources on the fly, but ... I don't know how! A change of question: How do I create on-the-fly resources or menu items with new, non-existing IDs? If I'd know, how to create on-the-fly resources, than I could stay with the normal WM_COMMAND system. Thanks to you Prasad! Best regards, and a happy weekend! Martin Lemburg