在对话框程序中操作菜单项

 在做基于对话框的程序时,有时我们要在这个对话框中加载菜单,于是可能要在对话框程序代码中修改菜单荐的状态或操作菜单项的其它操作,可是当我们用代码操作菜单项时:

  

GetMenu()->GetSubMenu(0)->EnableMenuItem(ID_ISP_DISPLAYMEMORY,MF_BYCOMMAND | MF_ENABLED);

编译时没什么问题,运行时,程序直接崩溃.该怎么解决这个问题呢?

在网上搜了很多资料,大部分都是说在得在框架类的构造函数内如下修改:

 

CMainFrm::CMainFrm { // Other stuff this->m_bAutoMenuEnable = true; } 

即改为"true"就可以了.

可是哥写的是对话框程序!!! 哪来的构架类????

这个问题该怎么解决呢?? 经过坚持不懈的查找,终于找到了解决方法:

第一步: 为对话框类 添加WM_INITMENUPOPUP消息.

              方法: 在对话框类的属性面板上方点一下那个Message按扭, 在消息列表中找到WM_INITMENUPOPUP,并添加此消息处理函数.

第二步: 在WM_INITMENUPOPUP消息处理函数内添加如下代码:

void CLPC1114UpdaterDlg::OnInitMenuPopup(CMenu* pPopupMenu, UINT nIndex, BOOL bSysMenu){CDialogEx::OnInitMenuPopup(pPopupMenu, nIndex, bSysMenu);// TODO: Add your message handler code hereASSERT(pPopupMenu != NULL);// Check the enabled state of various menu items.CCmdUI state;state.m_pMenu = pPopupMenu;ASSERT(state.m_pOther == NULL);ASSERT(state.m_pParentMenu == NULL);// Determine if menu is popup in top-level menu and set m_pOther to// it if so (m_pParentMenu == NULL indicates that it is secondary popup).HMENU hParentMenu;if (AfxGetThreadState()->m_hTrackingMenu == pPopupMenu->m_hMenu)state.m_pParentMenu = pPopupMenu;    // Parent == child for tracking popup.else if ((hParentMenu = ::GetMenu(m_hWnd)) != NULL){CWnd* pParent = this;// Child windows don't have menus--need to go to the top!if (pParent != NULL &&(hParentMenu = ::GetMenu(pParent->m_hWnd)) != NULL){int nIndexMax = ::GetMenuItemCount(hParentMenu);for (int nIndex = 0; nIndex < nIndexMax; nIndex++){if (::GetSubMenu(hParentMenu, nIndex) == pPopupMenu->m_hMenu){// When popup is found, m_pParentMenu is containing menu.state.m_pParentMenu = CMenu::FromHandle(hParentMenu);break;}}}}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);if (state.m_nID == 0)continue; // Menu separator or invalid cmd - ignore it.ASSERT(state.m_pOther == NULL);ASSERT(state.m_pMenu != NULL);if (state.m_nID == (UINT)-1){// Possibly a popup menu, route to first item of that popup.state.m_pSubMenu = pPopupMenu->GetSubMenu(state.m_nIndex);if (state.m_pSubMenu == NULL ||(state.m_nID = state.m_pSubMenu->GetMenuItemID(0)) == 0 ||state.m_nID == (UINT)-1){continue;       // First item of popup can't be routed to.}state.DoUpdate(this, TRUE);   // Popups are never auto disabled.}else{// Normal menu item.// Auto enable/disable if frame window has m_bAutoMenuEnable// set and command is _not_ a system command.state.m_pSubMenu = NULL;state.DoUpdate(this, FALSE);}// Adjust for menu deletions and additions.UINT nCount = pPopupMenu->GetMenuItemCount();if (nCount < state.m_nIndexMax){state.m_nIndex -= (state.m_nIndexMax - nCount);while (state.m_nIndex < nCount &&pPopupMenu->GetMenuItemID(state.m_nIndex) == state.m_nID){state.m_nIndex++;}}state.m_nIndexMax = nCount;}}

ok,接下来就可以用

GetMenu()->GetSubMenu(0)->EnableMenuItem(ID_ISP_DISPLAYMEMORY,MF_BYCOMMAND | MF_ENABLED);

这个函数来设置菜单项的状态了.

 

参考:http://support.microsoft.com/default.aspx?scid=kb;en-us;242577