disableing menu items - mfc
Author
I have an MFC program with:
CMenu menu1;
menu1.LoadMenu(IDR_MENU1);
SetMenu(&menu1);
now this loads a menu perfectly fine.
When I cleck file new (ID_FILE_NEW) I want to disable it, so it cant be pressed again.
Im trying:
menu1.EnableMenuItem(ID_FILE_NEW,MF_BYCOMAND|MF_GRAYED);
now this returns -1 suggesting the menu item doesn't exist, but when I click on the new button in the resource editor, it says ID ID_FILE_NEW
so what am I doing wrong? I have been googleing for ages but no success
Try this:
CMenu* mmenu = GetMenu();
CMenu* submenu = mmenu->GetSubMenu(0);
submenu->EnableMenuItem(ID_FILE_NEW, MF_BYCOMMAND | MF_DISABLED | MF_GRAYED);
CMenu* mmenu = GetMenu();
CMenu* submenu = mmenu->GetSubMenu(0);
submenu->EnableMenuItem(ID_FILE_NEW, MF_BYCOMMAND | MF_DISABLED | MF_GRAYED);
Author
nope, it just displayed the menu as normal.
here is my code:
here is my code:
class MFC_Tutorial_Window :public CFrameWnd{ CMenu menu1; // dedines my menu public: HANDLE tThread; MFC_Tutorial_Window() { Create(NULL,"Countdown - ALPHA V 0.2"); // creates window menu1.LoadMenu(IDR_MENU1); // sets up menu SetMenu(&menu1); // UINT t = menu1.EnableMenuItem // here I want to grey out the new button.(ID_FILE_NEW,MF_BYCOMMAND|MF_GRAYED); } void OnClickNew(); // defines function for when the new button is clicked void OnClickStatusT1(); void OnClickExitApp(); void OnClickAbout(); int OnCreate(LPCREATESTRUCT lpCreateStruct); void OnClose(); DECLARE_MESSAGE_MAP() // sets up a message map, for message handling};
Author
OK, ive still not had any luck, It just doesn't grey out. should I try creating the menu at runtime rather than as a resource?
I haven't touched MFC in ages, but I think this is the cause. Before displaying a menu MFC updates each menu item automatically. If it's missing an ON_COMMAND entry in a message map somewhere the menu item is automatically disabled, otherwise it's automatically enabled. CWinApp might have an update handler for ID_FILE_NEW by default, which is what is enabling the menu again.
This page describes a way to disable this. In your constructor for MFC_Tutorial_Window try adding this:
Update: Fixed incorrect information.
This page describes a way to disable this. In your constructor for MFC_Tutorial_Window try adding this:
MFC_Tutorial_Window(){ m_bAutoMenuEnable = false;}Update: Fixed incorrect information.
Author
ok, I tried that but I'm getting an unresolved external. heres my message map
class MFC_Tutorial_Window :public CFrameWnd{ CMenu menu1; // dedines my menu public: HANDLE tThread; MFC_Tutorial_Window() { m_bAutoMenuEnable = false; Create(NULL,"Countdown - ALPHA V 0.2"); // creates window menu1.LoadMenu(IDR_MENU1); // sets up menu SetMenu(&menu1);// UINT t = menu1.EnableMenuItem(ID_FILE_NEW,MF_BYCOMMAND|MF_GRAYED); } void OnClickNew(); // defines function for when the new button is clicked void OnClickStatusT1(); void OnClickExitApp(); void OnClickAbout(); int OnCreate(LPCREATESTRUCT lpCreateStruct); void OnClose(); void OnUpdateFileNew(CCmdUI* pCmdUI); DECLARE_MESSAGE_MAP() // sets up a message map, for message handling};BEGIN_MESSAGE_MAP( MFC_Tutorial_Window, CFrameWnd) // begining of message map ON_WM_CREATE() ON_WM_CLOSE() ON_COMMAND(ID_FILE_NEW,OnClickNew) // when new is clicked do function OnClickNew() ON_COMMAND(ID_HELP_ABOUT,OnClickAbout) ON_COMMAND(ID_STATUS_TIMER1,OnClickStatusT1) ON_COMMAND(IDEXIT,OnClickExitApp) ON_UPDATE_COMMAND_UI(ID_FILE_NEW,OnUpdateFileNew) // unresolved external hereEND_MESSAGE_MAP() // end of message mapvoid OnUpdateFileNew(CCmdUI* pCmdUI){ pCmdUI->Enable(false);}void MFC_Tutorial_Window::OnClickNew() // what to do when new is clicked{ newDialog dlg; //defines dialog box dlg.DoModal();}...
Oh, I probably should've worded things clearer.
Solution 1: Add the m_bAutoMenuEnable line. I don't know if this works.
Solution 2: Add ON_UPDATE_COMMAND_UI, this is probably the preferred solution since it integrates into MFC's message map, command updating framework. Ahh I wrote out a bunch of stuff describing how to implement it. Turns out you're just missing one thing.
Of course now you won't be able to click the ID_FILE_NEW menuitem since it'll always be disabled. If you want to disable it after one click, try this:
Solution 1: Add the m_bAutoMenuEnable line. I don't know if this works.
Solution 2: Add ON_UPDATE_COMMAND_UI, this is probably the preferred solution since it integrates into MFC's message map, command updating framework. Ahh I wrote out a bunch of stuff describing how to implement it. Turns out you're just missing one thing.
void OnUpdateFileNew(CCmdUI* pCmdUI)// should bevoid MFC_Tutorial_Window::OnUpdateFileNew(CCmdUI* pCmdUI)Of course now you won't be able to click the ID_FILE_NEW menuitem since it'll always be disabled. If you want to disable it after one click, try this:
class MFC_Tutorial_Window : public CFrameWnd{ bool m_bEnableFileNew; MFC_Tutorial_Window() { m_bEnableFileNew = true; // ... } // ...}void OnUpdateFileNew(CCmdUI* pCmdUI){ // the nice thing about this is that it'll also disable toolbar buttons that // have an ID of ID_FILE_NEW pCmdUI->Enable(m_bEnableFileNew);}void MFC_Tutorial_Window::OnClickNew(){ // disable file new. next time the menu displays MFC will call OnUpdateFileNew, // which will disable the menu item. m_bEnableFileNew = false; newDialog dlg; dlg.DoModal();}// ...This topic is closed to new replies.
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