资源编辑器中所有弹出菜单是否需添加虚拟菜单项？菜单层级疑问

Hey Andrew, let's tackle your two questions about MFC menu handling clearly:

Short answer: Yes, in most cases you do—but let's clarify what this means.

In MFC's menu resource system, popup menus can't exist in isolation. Every popup menu must be attached to a parent menu item. When you create a nested popup menu (like your pMnuSwap which is a sub-popup of pMnuPopup), the resource editor requires you to add a parent menu item that acts as the "trigger" for the popup. Even if this item is never displayed (e.g., it's a hidden or placeholder entry), it's necessary to define the hierarchy in the resource file.

Think of it like a tree: the top-level menu (IDR_MENU_MWB_SWAP) is the root, each popup is a child node, and each child node needs a parent node (a menu item) to connect it to the tree. Without that parent item, the resource editor has no way to associate the popup menu with the rest of the menu structure, and MFC won't be able to load or traverse it correctly.

Your code uses mnuContext.LoadMenu(IDR_MENU_MWB_SWAP) to load the entire top-level menu resource. Let's break down the hierarchy logic:

• mnuContext is the root menu (the top-level menu bar or context menu defined by IDR_MENU_MWB_SWAP).
• pMnuPopup = mnuContext.GetSubMenu(0) fetches the first popup menu attached to the root menu's first item. This is because the root menu's items are either command items or popup triggers—GetSubMenu(n) returns the popup menu linked to the nth item of the current menu.
• pMnuSwap = pMnuPopup->GetSubMenu(0) then fetches the popup menu attached to the first item of pMnuPopup.

You can't skip the hierarchy because:

• MFC loads the entire menu tree as a single resource when you call LoadMenu with the top-level ID. There's no direct way to load a nested popup menu by ID unless you explicitly assign a separate resource ID to it (which is not standard practice for nested popups).
• Each popup menu is a child of a specific menu item in its parent menu. The only way to access it is to navigate down from the root, following the parent-child relationships defined in your resource.

To visualize your menu structure (as defined in resources):

IDR_MENU_MWB_SWAP (Root Menu)
└── Menu Item 0 (trigger for pMnuPopup)
    └── pMnuPopup (Popup Menu)
        └── Menu Item 0 (trigger for pMnuSwap)
            └── pMnuSwap (Nested Popup Menu)

That's exactly the hierarchy your code is traversing to reach the nested pMnuSwap menu.

内容的提问来源于stack exchange，提问作者Andrew Truckle