Advanced MFC Programming

Chapter 2. Menu
void CMenuDoc::OnEditInsertDynamicMenu()
{
CMenu *pTopMenu=AfxGetMainWnd()->GetMenu();
CMenu *ptrMenu=m_menuSub.GetSubMenu(0);
pTopMenu->InsertMenu
(
1, MF_BYPOSITION | MF_POPUP, (UINT)ptrMenu->GetSafeHmenu(), "&Dynamic Menu"
);
AfxGetMainWnd()->DrawMenuBar();
m_bSubMenuOn=TRUE;
}
void CMenuDoc::OnEditDeleteDynamicMenu()
{
CMenu *pTopMenu=AfxGetMainWnd()->GetMenu();
pTopMenu->RemoveMenu(1, MF_BYPOSITION);
AfxGetMainWnd()->DrawMenuBar();
m_bSubMenuOn=FALSE;
}
When inserting sub-menu, flag MF_BYPOSITION is used. This is because the first level menu items do
not have command IDs.
After the menu is inserted or removed, we must call function CWnd::DrawMenuBar() to let the menu be
updated. Otherwise although the content of the menu is actually changed, it will not be reflected to the user
interface until the update is triggered by some other reasons.
2.4 Bitmap Check
The default menu check provided by MFC is a tick mark, and nothing is displayed when the check is
removed. With a little effort, we can prepare our own bitmaps and use them to implement the checked and
unchecked state (Figure 2-3).
To implement the checked and unchecked states of menu items using bitmaps, we need to call the
following member function of CMenu:
BOOL CMenu::SetMenuItemBitmaps
(
UINT nPosition, UINT nFlags, const CBitmap* pBmpUnchecked,
const CBitmap* pBmpChecked
);
The first two parameters of this function indicate which menu item we are working with. Their
meanings are the same with that of functions such as CMenu::EnableMenuItem(…). When calling this
function, we can use either a command ID or an absolute position to identify a menu item. The third and
fourth parameters are pointers to bitmaps (CBitmap type objects), one for checked state, one for unchecked
state.
Bitmap checks
Standard checks
Figure 2-3. Standard menu checks and bitmap menu checks
Like menu, bitmap can also be prepared as resource then be loaded at program’s runtime. We can edit
a bitmap in Developer Studio, and save it as application’s resource. Adding a bitmap resource is the same
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