MFC Edit control message handle access Document object - c++

I create a new class extend CEdit to override some of the message handles.
My ultimate goal is when edit control is on focus, some of the toolbar buttons become available.
I created a bool variable in doc. then the pCmdUI->enable() set to this bool. The onfocus is overridden in new edit control class. I'm having trouble to update this bool vairbale from the onfocus message handle.
void CMFCDoc::OnUpdateTextColor(CCmdUI *pCmdUI)
{
// TODO: Add your command update UI handler code here
pCmdUI->Enable(shape_onfocus_);
}
class CMFCDoc : public COleServerDoc
{
...
bool shape_onfocus_;
}
//edit control
#include <afxwin.h>
class CEditControl :
public CEdit
{
public:
CEditControl();
~CEditControl();
DECLARE_MESSAGE_MAP()
afx_msg void OnEnSetfocus();
};
void CEditControl::OnEnSetfocus()
{
//----- I want to update shape_onfocus_ here. -----
this->SetWindowTextA(_T("Hello world"));
}

Assuming your CEditControl instance is a child of some sort of CView, you could go about it like this:
void CEditControl::OnEnSetfocus()
{
CView *view = static_cast<CView *>(GetParent());
CMFCDoc *doc = static_cast<CMFCDoc *>(view->GetDocument());
doc->shape_onfocus_ = true;
...
}

Assuming the edit-control is a child of a CView-derived class, you should better put the OnUpdateUI() handler in the view class, not the document one.
For example, if the view-class is CFormView-derived (dialog), you could simply write:
void CMyView::OnUpdateTextColor(CCmdUI *pCmdUI)
{
pCmdUI->Enable(GetFocus()==GetDlgItem(IDC_MYEDIT));
}
This piece of code works for both SDI and MDI applications.
If the view class is not CFormView-derived (the edit-box was created programmatically), the code above could be modified slightly, and instead of calling GetDlgItem() you should enumerate the view's children list (search your edit-box there).
If the only reason to override the edit-control was to capture the EN_SET/KILLFOCUS messages, sorry this wasn't worth the effort, as you could simply capture these in the view's code. Then the view's message-map would contain:
ON_EN_SETFOCUS(IDC_MYEDIT, &CMyView::OnEnSetfocusMyEdit)
ON_EN_KILLFOCUS(IDC_MYEDIT, &CMyView::OnEnKillfocusMyEdit)
and the view-class code:
void CMyView::OnEnSetfocusMyEdit()
{
// TODO: Add your control notification handler code here
}
void CMyView::OnEnKillfocusMyEdit()
{
// TODO: Add your control notification handler code here
}
These are generated by the wizard. Go to the Class View tab, select your class and then go to the Events page; in the Controls subtree you can find your control and add handlers for its events. But all this is not needed, as you can just use GetFocus()/GetDlgItem() as suggested above.
And as other members said, you can access the document class from any of its views by calling the GetDocument() function.

Related

Create MFC controls in CDialog constructor [win32/MFC]

I'm working on the library, that wraps some MFC classes and methods. I want the user to be able to dynamically create a CDialogEx using a template in memory. For the modal dialogs, I call CDialog::InitModalIndirect and then CDialog::DoModal. For the modeless dialogs, I call CDialog::CreateIndirect and then CWnd::Show.
The code looks something like this:
// inside my library
class MyDialog : public CDialogEx
{
public:
MyDialog(CWnd* parent) : CDialogEx()
{
parent_ = parent;
my_template_data_ = CreateSomeGenericTemplate();
// OnInitDialog should be preferably called here
}
void ShowModal()
{
InitModalIndirect(my_template_data_, parent_);
DoModal(); // but it's called here - too late
}
void ShowModeless()
{
CreateIndirect(my_template_data_, parent_);
Show(); // but it's called here - too late
}
MyButton* GetButton(int id)
{
// returns the instance of my MyButton, which is a subclassed CButton
}
private:
BOOL MyDialog::OnInitDialog() override
{
CDialogEx::OnInitDialog();
// CWnd::Create for the UI controls can only be called here
}
};
// user's code
// user creates the dialog - in the constructor it's not clear if modal or modeless
1. MyDialog user_dialog(some_parent); // here, I need the controls to be created
2. user_dialog.GetButton(42)->SetWindowText(L"new text"); // user wants to initialize his controls
// but he can't, because MyButton::Create was not called yet
3. user_dialog.ShowModal(); // and only then display the dialog
//by default, here the MFC calls OnInitDialog - too late,
//the SetText method needed to be set on line 2.
My problem is, that the dialog's controls (buttons etc.) can only be created inside the CDialog::OnInitDialog method, which is called automatically after DoModal (for modal)/Show (for modeless) methods. I need the controls to be created and properly initialized (with the CWnd::Create method) preferably inside the constructor. I thought about calling Show/DoModal directly inside the constructor but I don't yet know if it's going to be modal or modeless dialog. It there a solution to this? Many thanks in advance.
Why don't you refactor your code and put the common code in a InitUI() method and call it from both sides?
And don't init interface on the constructor. Do it in OnInitDialog for modal; and in Create, or OnCreate (which implies a ON_WM_CREATE() map entry) for modeless dialogs.

How to change MFC View by clicking a Button inside the MainFrame

I want to change the presented View by clicking a button inside the Window
like this.
My Project settings:
I made an MFC Project (SDI) without Doc/View support.
I made two more Views in the Designer and added Classes to them. The new View Classes are derived from CFormView. I changed the Constructor and Destructor of the new View Classes to public.
Added them as pointers to MainFrm.h:
CMainView* m_pMainView;
CSecondView* m_pSecondView;
I changed the OnCreate(),OnSetFocus() and OnCmdMsg() Method of MainFrm.cpp like this:
(That allows to present the FormView I made with the Designer)
int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CFrameWnd::OnCreate(lpCreateStruct) == -1)
return -1;
// First, build the view context structure
CCreateContext ccx;
// Designate the class from which to build the view
ccx.m_pNewViewClass = RUNTIME_CLASS(CMainView);
// Using the structure, create a view
m_pMainView = DYNAMIC_DOWNCAST(CMainView, this->CreateView(&ccx));
if (!m_pMainView)
{
TRACE0("creation of view failed");
}
// Do layout recalc
RecalcLayout();
// Show the view and do an initial update
m_pMainView->ShowWindow(SW_SHOW);
m_pMainView->OnInitialUpdate();
// Set this view active
SetActiveView(m_pMainView);
// Order it to resize the parent window to fit
m_pMainView->ResizeParentToFit(FALSE);
return 0;
}
...
void CMainFrame::OnSetFocus(CWnd* /*pOldWnd*/)
{
m_pMainView->SetFocus();
}
BOOL CMainFrame::OnCmdMsg(UINT nID, int nCode, void* pExtra, AFX_CMDHANDLERINFO* pHandlerInfo)
{
if (m_pMainView->OnCmdMsg(nID, nCode, pExtra, pHandlerInfo))
return TRUE;
return CFrameWnd::OnCmdMsg(nID, nCode, pExtra, pHandlerInfo);
}
Now here comes my problem! I have a button on the First presented View and if you click on it, the view should change. I made the following function with the event handler in the Designer:
void CMainView::OnBnClickedButton1()
{
// What to do here? I want to change the current view to another View by clicking the button
}
If i handle it in the MainFrm.cpp class for example with menue buttons it is no problem... that works fine:
void CMainFrame::OnViewNextview()
{
CCreateContext ccx2;
ccx2.m_pNewViewClass = RUNTIME_CLASS(CSecondView);
m_pSecondView = DYNAMIC_DOWNCAST(CSecondView, this->CreateView(&ccx2));
RecalcLayout();
m_pMainView->ShowWindow(SW_SHOW);
m_pMainView->OnInitialUpdate();
SetActiveView(m_pMainView);
m_pMainView->ResizeParentToFit(FALSE);
}
I tried to write a function in CMainFrame and call this function in CMainView::OnBnClickedButton1() but I don't know how to get the current MainFrm Object. A pointer on MainFrm or a member of it in CMainView did not work.
I searched and red tutorials for days to solve my problem. I also tried it with Doc/View support like shown here:
https://learn.microsoft.com/en-us/cpp/mfc/adding-multiple-views-to-a-single-document?view=vs-2019 but i dont know where to call switchView() correctly.
Maybe anyone can help...
First, you shouldn't really be overriding OnCmdMsg - instead, use DECLARE_MESSAGE_MAP in your header file and BEGIN_MESSAGE_MAP/END_MESSAGE_MAP in your implementation file, and insert handler messages between those two macros.
I see that you already have a handler in your CMainView class for the button click! From here, you should call the CMainFrame function to change to the next view - just as you do when the menu command is given (which you say works). Make that function public and give the MainView class access to a pointer to the main frame (or use AfxGetMainWnd() and cast it to a pointer of your class). Something like this:
void CMainView::OnBnClickedButton1()
{
AfxGetMainWnd()->PostMessage(WM_COMMAND, menuID); // ID of menu command that works!
}
Big hugs for Adrian, i got it to work!
I also added a third view successfully :)
It is very IMPORTANT , to HIDE the last shown Window if you want to implement more views. you can do it like:
void CMainFrame::OnView3()
{
CCreateContext ccx3;
ccx3.m_pNewViewClass = RUNTIME_CLASS(CThirdView);
m_pThirdView = DYNAMIC_DOWNCAST(CThirdView, this->CreateView(&ccx3));
RecalcLayout();
m_pSecondView->ShowWindow(SW_HIDE); // Hide the last Window
m_pThirdView->ShowWindow(SW_SHOW); // Show the new Window
m_pThirdView->OnInitialUpdate();
SetActiveView(m_pThirdView);
//m_pThirdView->ResizeParentToFit(FALSE); //if you call this, the size of the window is the same like in the Designer
}

Typecasting EventHandler in C++/CLI

I have a form (which I'll call MainForm) embedded with a TabControl. Every time the user creates a new tab it is filled with an instance of a pre-built Panel (which I'll call MyPanel) which contains many controls.
My MyPanel class has a private variable bool save_state which is set to false every time one of the (editable) controls is edited and set to true when the user "saves" the state of the panel.
I want a visual flag to keep track of tabs that have unsaved changes (e.g. the tab "Tab1" will instead display the text "Tab1 *" if it has unsaved changes). So I want to set up the event handler in my MainForm which can call a method in MyPanel to add the handler to each control.
Since not all my controls use the same EventHandler type (for example, I also need to track DataGridViewRowsAddedEvent, among others), I currently have several methods adding the appropriate handler to the corresponding controls (one for each type of Event Handler), each of which is running the same code (i.e. set the save_state bit to false and append " *" to the tab text.
For example, in MainForm.cpp I have:
#include "MyPanel.h"
void markUnsaved(void) {
// set panel bit to false
// append " *" to tab text if we haven't already
}
void MainForm::handler1(Object ^sender, EventArgs ^e) {
markUnsaved();
}
void MainForm::handler2(Object ^sender, DataGridViewRowsAddedEventArgs ^e) {
markUnsaved();
}
void Main::FormaddNewPanelToTab(int tab_index) {
// check index is valid ...
// make the new panel
MyPanel ^new_panel = gcnew MyPanel();
new_panel->addEventHandlerToControls(gcnew EventHandler(this, &MainForm::handler1));
new_panel->addDgvEventHandlerToControls(gcnew DataGridViewRowsAddedEventHandler(this, &MainForm::handler2));
// rest of code...
}
Though this currently works as intended, this (along with the several other Event Handler types I have to manage) makes my code look really silly.
I am hoping to be able to have have a single event handler in MainForm and a single method in MyPanel which type-casts the Event Handler passed and adds it to all the controls with the appropriate types.
I have tried doing simple casts such as:
void MyPanel::addHandlerToControls(EventHandler ^handler) {
control_NUD->ValueChanged += handler; // this works because ValueChanged is of type EventHandler
control_DGV->RowsAdded += (DataGridViewRowsAddedEventHandler ^)handler; // this compiles but throws an exception
// rest of the code...
}
to no avail.
Any help would be greatly appreciated!
I know this is maybe a bit late for answer but I'd want to show how would I solve this.
Firs of all I suggest to get rid from idea of casting event handlers. Kind of such approach may work in C# (with some adjustments) but as far as I know it's not possible in C++ /CLI.
I'd go for adding new event to a MyPanel class that will be invoked every time when the data on a panel is changed. But to avoid adding a lot of different handlers to a control events in a MyPanel class it's better to create one generic method that will handle all the neccessary control's events and fire new event. Maybe this sounds messy, let me show the code:
public ref class MyPanel
{
// Add a new event
public:
event EventHandler^ DataChanged;
// Add a method that will fire new event
// this methid will be invoked on every control's event that you'll subscribe
private:
generic <typename T>
void DataChangedHandler(System::Object^ sender, T e)
{
// Fire the event
DataChanged(this, EventArgs::Empty);
}
// Once the controls are initialized you may add the event handlers
// I put it in a constructor only for example
MyPanel()
{
control_NUD->ValueChanged += gcnew EventHandler(this, &MyPanel::DataChangedHandler<EventArgs^>);
control_DGV->RowsAdded += gcnew DataGridViewRowsAddedEventHandler(this, &MyPanel::DataChangedHandler<DataGridViewRowsAddedEventArgs^>);
// and so on...
}
}
/// And now in a main form we only need to subscribe to a DataChanged event
public ref class MainForm
{
//...
// the handler
void MyHandler(Object^ sender, EventArgs^ e)
{
markUnsaved();
}
void FormaddNewPanelToTab(int tab_index)
{
// make the new panel
MyPanel ^new_panel = gcnew MyPanel();
new_panel->DataChanged += gcnew EventHandler(this, &MainForm::MyHandler);
}
//...
}
Hope this helps.

What's wrong with my attempt at subclassing CButton?

I tried to create a subclassed control for the first time, but I feel like I did something wrong. The control is a Button, which I placed in the designer. This is its class:
class TTTField : public CButton
{
public:
BEGIN_MSG_MAP_EX(TTTField)
MSG_WM_INITDIALOG(OnInitDialog);
END_MSG_MAP()
TTTField operator=(const CWindow& btn);
private:
const BOOL OnInitDialog(const CWindow wndFocus, const LPARAM lInitParam);
};
Nothing fancy so far.
However, I can't really achieve to receive windows messages in this control. This is bad, considering the main reason for trying to subclass a control was the fact that this should be a reusable class with reusable, custom Paint behaviour. I want to overwrite certain message handlers, while keeping those I didn't explicitely ask for to the usual CButton routine.
As you can see, I implemented a message map, but the messages are just not coming in.
This is how I tried to setup the instance of this class:
TTTField fld;
is a member variable of my main dialog class. In this class I added the following DDX_MAP:
BEGIN_DDX_MAP(TTTMainDialog)
DDX_CONTROL_HANDLE(IDC_BTN, fld)
END_DDX_MAP()
with IDC_BTN being the id of the button on the designer.
In the assignment operator overload for TTTField I have the following:
TTTField TTTField::operator=(const CWindow& btn)
{
Attach(btn);
return *this;
}
I feel like this operator overload might be the source of my problems, but I just can't manage to find a website which is properly explaining the whole topic without using code which seems outdated for like 20 years.
What am I doing wrong here? I am really lost right now.
The button class should be defined as follows:
class TTTField : public CWindowImpl<TTTField, CButton>
{
protected:
BEGIN_MSG_MAP_EX(TTTField)
MSG_WM_LBUTTONDOWN(OnLButtonDown)
END_MSG_MAP()
protected:
LRESULT OnLButtonDown(UINT, CPoint)
{
//Edit: this override is meant for testing the subclass only
//it's insufficient for handling button clicks
MessageBox(L"Testing override...");
return 0;
}
};
Override dialog box's OnInitDialog, call SubclassWindow to subclass the button:
class TTTMainDialog: public CDialogImpl<CMainDialog>
{
public:
enum { IDD = IDD_MYDIALOG };
BEGIN_MSG_MAP(TTTMainDialog)
MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
END_MSG_MAP()
TTTField fld;
LRESULT OnInitDialog(UINT nMessage, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
{
fld.SubclassWindow(GetDlgItem(IDC_BTN));
return 0;
}
};
Edit, for initialization
class TTTField : public CWindowImpl<TTTField , CButton>
{
public:
void Create(CWindow *wnd, int id)
{
SubclassWindow(wnd->GetDlgItem(id));
//add initialization here
}
...
}
Then to create the button:
//fld.SubclassWindow(GetDlgItem(IDC_BTN));
fld.Create(this, IDC_BTN); //<== use this instead
Perhaps the best example, or at least one of, of subclassing a button is right in the sources of WTL, at the top of atlctrlx.h:
template <class T, class TBase = CButton, class TWinTraits = ATL::CControlWinTraits>
class ATL_NO_VTABLE CBitmapButtonImpl : public ATL::CWindowImpl< T, TBase, TWinTraits >
{
public:
DECLARE_WND_SUPERCLASS(NULL, TBase::GetWndClassName())
...
You will also file external resources on this class: Using WTL's CBitmapButton.
That's not to mention WTL's comment on doing the controls:
// These are wrapper classes for Windows standard and common controls.
// To implement a window based on a control, use following:
// Example: Implementing a window based on a list box
//
// class CMyListBox : CWindowImpl<CMyListBox, CListBox>
// {
// public:
// BEGIN_MSG_MAP(CMyListBox)
// // put your message handler entries here
// END_MSG_MAP()
// };
More examples of simple and sophisticated custom WTL controls can be found at viksoe.dk.
A confusing thing about WTL control extension is that basic classes like CButton, CComboBox are thin wrappers over standard controls. They mostly translate methods into messages to be sent. You can often easily cast instances of such classes to HWND and back.
Standard controls themselves offer a level of customization through support of notification messages.
When you subclass a control, you are adding functionality on your side which somehow needs to interoperate with stock implementation, and control classes are no longer thin wrappers. Hence, you inherit from CWindowImpl and not CButton directly. Next challenge is to specifically subclass: you need to have original window created and after that, having a HWND handle, you modify it to route the messages through your message map. This is where you need SubclassWindow method. That is, you have the control created, you look it up its handle, e.g. with GetDlgItem and then you subclass the window using your class instance SubclassWindow call. Or, alternatively you can create the control using your new class Create method in which case CreateWindow and association with your message map will be done for you.
Some, more complicated, implementations of custom controls will also want you to reflect notification messages from parent window to the controls, so that they could handle them within the same custom control class. This will typically require that you add a line REFLECT_NOTIFICATIONS in your dialog class message map (see this related question on this).

MFC RibbonBar -- programmatically minimize?

The MFC ribbon bar has a menu item labelled 'Minimize the ribbon'. When you select it, only the headers of each category are shown, and the ribbon pops up when the headers are clicked. I'd like to programmatically force a ribbon into this state. Unfortunately, the only method I can find is ToggleMimimizeState() [sic], which will either put it into this state or take it out depending on its current state.
Looking at the MFC source code, the way the menu command works is through this code:
case idMinimize:
if (m_pActiveCategory != NULL)
{
ASSERT_VALID(m_pActiveCategory);
m_pActiveCategory->ShowElements(FALSE);
RedrawWindow();
}
m_pActiveCategory can be obtained from outside of the CMFCRibbonBar class through the GetActiveCategory() method, but unfortunately the category's ShowElements() method is protected and I cannot see a way of achieving the same effect with the public methods.
Neither does there seem to be an obvious way of determining whether the ribbon is currently minimized.
Is there something I'm missing, or do I just have to guess at the current state?
Derive two new classes from CMFCRibbonBar and CMFCRibbonCategory
class MyCMFCRibbonCategory: public CMFCRibbonCategory
{
public:
void force_ShowElements(BOOL todo)
{
ShowElements(todo);
}
};
class MyRibbonBar: public CMFCRibbonBar
{
public:
BOOL is_minimized()
{
return m_dwHideFlags == AFX_RIBBONBAR_HIDE_ELEMENTS;
}
void minimize_me(BOOL show_minimized)
{
MyCMFCRibbonCategory* cc = (MyCMFCRibbonCategory*)GetActiveCategory();
if (cc != NULL)
{
cc->force_ShowElements(!show_minimized);
RedrawWindow();
}
}
};
then change in your CMainframe from
CMFCRibbonBar m_wndRibbonBar;
to
MyRibbonBar m_wndRibbonBar;
Now in your code you can use the new two members:
BOOL MyRibbonBar::is_minimized()
void MyRibbonBar::minimize_me(BOOL show_minimized)
Basic example:
void CMainFrame::OnButton2()
{
if( m_wndRibbonBar.is_minimized() )
m_wndRibbonBar.minimize_me(FALSE);
else
m_wndRibbonBar.minimize_me(TRUE);
}
Hope it can help.
A combination of the above worked for me. That is, I wanted to use the Ribbon as a tabbed set of extra functions on a main menu. However, I didn't want the ribbon to have the ability to stay maximized. I only wanted the user to click, see a few actions and after that, disappear.
In short, prevent the ribbon from docking, or staying maximized. Whatever you want to call it. Click a tab, then and icon on the ribbon and disappear.
Instructions:
I derived my own CMyRibbon class by inheriting from CMFCRibbonBar. (Done using Class wizard and making an MFC class)
Create an event handler for WM_SIZE in our new CMyRibbon class (ClassWizard)
void CMyRibbon::OnSize(UINT nType, int cx, int cy)
{
CMFCRibbonBar::OnSize(nType, cx, cy);
if (!(GetHideFlags() & AFX_RIBBONBAR_HIDE_ELEMENTS))
ToggleMimimizeState();
}
In CMainFrm.h add this change:
CMyRibbon m_wndRibbonBar;
Use m_wndRibbonBar.ToggleMimimizeState();
Simply check (m_wndRibbonBar.GetHideFlags() & AFX_RIBBONBAR_HIDE_ELEMENTS) value.