我正在开发MFC MDI应用程序。我想有选择地启用或禁用一些右键单击上下文菜单命令,但是在使用ON_UPDATE_COMMAND_UI禁用某些命令来实现功能后,菜单命令仍然保持活动状态。
似乎在适当的时间未触发或处理ON_UPDATE_COMMAND_UI消息。
目标是实现取决于所选树元素的CTreeCtrl上下文菜单。
主CWinAppEx启动CMDIFrameWndEx。 CMDIFrameWndEx对象包含普通的MDI子框架,但它还包含一个CDockablePane,它本身包含一个CTreeCtrl,旨在与Visual Studio中的Project或Solution树视图类似地使用。
我在从CTreeCtrl继承的类中实现了ON_UPDATE_COMMAND_UI消息处理程序。 当我单击菜单项本身时,将调用这些处理程序,但是为时已晚;应该在菜单打开之前调用它们。
我怀疑这与命令(或消息)路由有关;环顾四周表明某些控件或窗口类未收到ON_COMMAND_UPDATE_UI消息,因为它们是在CFrameWnd级别处理的。但是,这些讨论中提出的解决方法或解决方案并未明确说明。我想遵守常见的MFC / MDI习惯用法,因此我希望对此问题进行一个较全面的,初学者级的解释。
CDockablePane窗口(或CTreeCtrl控件)是否不打算与ON_COMMAND_UPDATE_UI进行交互?为什么是这样?我还想念其他东西吗?
我的直觉是,无需亲自连接一堆事件就可以实现此目的,因为MFC框架应该将消息传递给可能处理它们的任何类。我开始认为我缺少这种行为的微妙之处。
从我的CTreeCtrl继承类(CLCPViewTree):
BEGIN_MESSAGE_MAP(CLCPViewTree, CTreeCtrl)
ON_NOTIFY_REFLECT(NM_RCLICK, OnRClick)
ON_COMMAND(ID_LCPGATEWAYCONTEXTMENU_SAVE_SESSION, SaveSession)
ON_COMMAND(ID_LCPGATEWAYCONTEXTMENU_LOAD_SESSION, LoadSession)
ON_COMMAND(ID_LCPGATEWAYCONTEXTMENU_SAVE, SaveDocument)
ON_COMMAND(ID_LCPGATEWAYCONTEXTMENU_LOAD, LoadDocument)
ON_UPDATE_COMMAND_UI(ID_LCPGATEWAYCONTEXTMENU_LOAD, OnUpdateMenuLoadSingle)
ON_UPDATE_COMMAND_UI(ID_LCPGATEWAYCONTEXTMENU_SAVE, OnUpdateMenuLoadSingle)
ON_UPDATE_COMMAND_UI(ID_LCPGATEWAYCONTEXTMENU_LOAD_SESSION, OnUpdateMenuLoadSession)
ON_UPDATE_COMMAND_UI(ID_LCPGATEWAYCONTEXTMENU_SAVE_SESSION, OnUpdateMenuSaveSession)
ON_WM_CONTEXTMENU()
END_MESSAGE_MAP()
afx_msg void CLCPViewTree::OnUpdateMenuLoadSingle(CCmdUI* pCmdUI)
{
pCmdUI->Enable(m_bShowSingleInstanceMenu);
}
afx_msg void CLCPViewTree::OnUpdateMenuSaveSingle(CCmdUI* pCmdUI)
{
pCmdUI->Enable(m_bShowSingleInstanceMenu);
}
afx_msg void CLCPViewTree::OnUpdateMenuLoadSession(CCmdUI* pCmdUI)
{
pCmdUI->Enable(m_bShowSessionMenu);
}
afx_msg void CLCPViewTree::OnUpdateMenuSaveSession(CCmdUI* pCmdUI)
{
pCmdUI->Enable(m_bShowSessionMenu);
}
void CLCPViewTree::OnRClick(NMHDR* pNMHDR, LRESULT* pResult)
{
TRACE0("CLCPViewTree::OnRClick()\r\n");
HTREEITEM hItem = GetSelectedItem();
if(!hItem)
{
return;
}
CString text = GetItemText(hItem);
TRACE0(text);
//To get your element:
SelectorReference* ref = (SelectorReference *) (GetItemData(hItem));
if(ref == nullptr)
{
m_bShowSessionMenu = false;
m_bShowSingleInstanceMenu = false;
}
else if(ref->is_program)
{
m_bShowSessionMenu = false;
m_bShowSingleInstanceMenu = true;
// Send WM_CONTEXTMENU to self
CString path = CString(ref->p_pd->ProgramPath) + "sim";
TRACE0("Controller path:\r\n");
TRACE0(path + "\r\n");
SelectedControllerPath = path;
SelectedLCPGatewayView = ref->view;
SendMessage(WM_CONTEXTMENU, (WPARAM) m_hWnd, GetMessagePos());
}
else
{
m_bShowSessionMenu = false;
m_bShowSingleInstanceMenu = false;
}
// Mark message as handled and suppress default handling
*pResult = 1;
}
void CLCPViewTree::OnContextMenu(CWnd* pWnd, CPoint ptMousePos)
{
// if Shift-F10
if (ptMousePos.x == -1 && ptMousePos.y == -1)
ptMousePos = (CPoint) GetMessagePos();
ScreenToClient(&ptMousePos);
CMenu menu;
CMenu* pPopup;
// the font popup is stored in a resource
menu.LoadMenu(IDR_PROGRAM_MENU);
pPopup = menu.GetSubMenu(0);
ClientToScreen(&ptMousePos);
pPopup->TrackPopupMenu( TPM_LEFTALIGN, ptMousePos.x, ptMousePos.y, this );
}
此后,我在我的CMDIFrameWndEx继承的类(CMainFrame)和我的CDockablePane继承的类(LCPSelector)中添加了对OnCmdMsg的替代。目的是将命令消息一直传递到CTreeCtrl对象,以防它们可能被处理。
我根据此处对命令路由的讨论添加了此代码:https://docs.microsoft.com/en-us/cpp/mfc/command-routing?view=vs-2019
不过仍然获得相同的结果。也许这是错误的方向,或者我也缺少其他东西。
供参考:CMainFrame继承自CMDIFrameWndEx,而LCPSelector继承自CDockablePane。
BOOL CMainFrame::OnCmdMsg(UINT id,int code , void *pExtra,AFX_CMDHANDLERINFO* pHandler)
{
//route cmd first to registered dockable pane
if(m_wndSelector.OnCmdMsg(id,code,pExtra,pHandler))
{
return TRUE;
}
return CMDIFrameWndEx::OnCmdMsg(id,code,pExtra,pHandler);
}
BOOL LCPSelector::OnCmdMsg(UINT id,int code , void *pExtra,AFX_CMDHANDLERINFO* pHandler)
{
//route cmd first to registered dockable pane
if(m_ctrlLCPViewTree.OnCmdMsg(id,code,pExtra,pHandler))
{
return TRUE;
}
return CDockablePane::OnCmdMsg(id,code,pExtra,pHandler);
}
打开菜单时,会生成WM_INITMENUPOPUP
消息,它会调用OnInitMenuPopup
。
[OnInitMenuPopup
根据ON_UPDATE_COMMAND_UI
更新菜单
如果您在popup->TrackPopupMenu(TPM_LEFTALIGN, x, y, this)
类中调用CTreeCtrl
,则必须自己处理OnInitMenuPopup
。否则,将忽略ON_UPDATE_COMMAND_UI
。
[在许多情况下,使用AfxGetMainWnd()
作为菜单父项的窗口句柄会更容易。这应该调用CFrameWnd::OnInitMenuPopup
,它将基于ON_UPDATE_COMMAND_UI
命令更新菜单项。
请确保将ON_COMMAND
和ON_UPDATE_COMMAND_UI
放在您的CDockablePane
或CMDIFrameWndEx
类中。示例:
BEGIN_MESSAGE_MAP(CMyDockablePane, CDockablePane)
ON_COMMAND(ID_X, OnFoo)
ON_UPDATE_COMMAND_UI(ID_X, OnFooUpdate)
...
END_MESSAGE_MAP()
...
//use AfxGetMainWnd() instead of this handle
popup->TrackPopupMenu(TPM_LEFTALIGN, pt.x, pt.y, AfxGetMainWnd());
CTreeCtrl
类中调用它,但是您必须覆盖OnInitMenuPopup
BEGIN_MESSAGE_MAP(CMyTreeCtrl, CTreeCtrl)
ON_WM_INITMENUPOPUP()
ON_COMMAND(ID_X, OnFoo)
ON_UPDATE_COMMAND_UI(ID_X, OnFooUpdate)
...
END_MESSAGE_MAP()
void CMyTreeCtrl::OnInitMenuPopup(CMenu* popup, UINT nIndex, BOOL bSysMenu)
{
if(popup && !bSysMenu)
{
CCmdUI state;
state.m_pMenu = popup;
state.m_nIndexMax = popup->GetMenuItemCount();
for(UINT i = 0; i < state.m_nIndexMax; i++)
{
state.m_nIndex = i;
state.m_nID = popup->GetMenuItemID(i);
state.DoUpdate(this, FALSE);
}
}
}
...
//call from CMyTreeCtrl with this handle
popup->TrackPopupMenu(TPM_LEFTALIGN, pt.x, pt.y, this);