Command Routing for Popup Menus

Introduction

While working with popup menus, I needed a way to hook these into the standard CCmdUI MFC OnUpdate interface. The following block of code does this:

void CmdRouteMenu(CWnd* pWnd,CMenu* pPopupMenu)
{
    CCmdUI state;
    state.m_pMenu = pPopupMenu;
    state.m_pParentMenu = pPopupMenu;
    state.m_nIndexMax = pPopupMenu->GetMenuItemCount();

    for (state.m_nIndex = 0; 
         state.m_nIndex < state.m_nIndexMax; 
         state.m_nIndex++) 
    {
        state.m_nID = pPopupMenu->GetMenuItemID(state.m_nIndex);

        // menu separator or invalid cmd - ignore it

        if (state.m_nID == 0) continue; 

        if (state.m_nID == (UINT)-1)
        {
            // possibly a popup menu, route to child menu if so

            CMenu* pSub=pPopupMenu->GetSubMenu(state.m_nIndex);
            if(pSub) CmdRouteMenu(pWnd,pSub);
        }
        else 
        {
            // normal menu item, Auto disable if command is 

            // _not_ a system command.

            state.m_pSubMenu = NULL;
            state.DoUpdate(pWnd, FALSE);
        }
    }
}

Usage Example:

CmdRouteMenu(pWnd,pSubMenu);
pSubMenu->TrackPopupMenu(TPM_LEFTBUTTON | TPM_RIGHTBUTTON | 
                         TPM_LEFTALIGN,point.x,point.y,pWnd,NULL);

Simply call with the window to handle the OnUpdate messages (usually your MainWnd) and the menu to be worked on, just before popping up the menu using TrackMenu(...). This also works for BMP menu and Gradient menu also found on CodeProject.

Of course, the code above only works if you have the OnUpdate calls written to handle the menu commands.