Unable to manage cbutton on_BN_CLICKED event on MFC

Question

0.00/5 (No votes)

See more:

I have been able to create a CButton in a CView derived class, and it is visible.
The problem is, no matter how and where I insert the ON_BN_CLICKED event management map entry, it seems the event is not fired or at least not propagated to the correct message map.
This is my CView derived class Initial update handler:

void CMFC_csv2hstView::OnInitialUpdate()  // 
{
	// TODO: add draw code for native data here
	RECT R;
	R.bottom = 250;
	R.top = 100;
	R.left = 100;
	R.right = 250; 
	
	/*CButton CB;*/
	CB.Create(_T("Hello"), WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON, R, this, 1);
	

}

and the related message map :

IMPLEMENT_DYNCREATE(CMFC_csv2hstView, CView)

BEGIN_MESSAGE_MAP(CMFC_csv2hstView, CView)
	// Standard printing commands
	ON_COMMAND(ID_FILE_PRINT, &CView::OnFilePrint)
	ON_COMMAND(ID_FILE_PRINT_DIRECT, &CView::OnFilePrint)
	ON_COMMAND(ID_FILE_PRINT_PREVIEW, &CMFC_csv2hstView::OnFilePrintPreview)
	ON_COMMAND(WM_CREATE, &CMFC_csv2hstView::OnCreateWindow)
	//ON_COMMAND(BN_CLICKED, &CMFC_csv2hstView::OnButton) //-->
	ON_BN_CLICKED(1, &CMFC_csv2hstView::OnButton)//-
	ON_WM_CONTEXTMENU()
	ON_WM_RBUTTONUP()
END_MESSAGE_MAP()

As you can see the "OnButton" method is my OnClick handler , where I put a breakpoint, but its never reached.It seems that, however you click the button, the event is not managed.

I have to say I made lots of tries before reaching this point, I tried to put the event handler in every possible message map around the application (even if sometimes it was clearly nonsense).
Some told me , that maybe the ID I was assigning to the CButton (1) was already in use, I tried to look in the application for other objects with the same ID but couldn't find it. Is there a way to assign an ID and be sure it's not already used ?

I looked around a lot of tutorials and online resources, it seems noone takes in consideration the eventuality of managing a Button without the use of Dialog Boxes.
Is this a rule ? is there a limit in MFC framework which makes it not possible to do what I want to do ?

The application is a MDI and I am using VS 2013 Community

What I have tried:

Putting :

ON_BN_CLICKED(1, &CMFC_csv2hstView::OnButton)

in CWinApp, MainFrm

Posted 11-Dec-17 19:24pm

tiwal

Updated 12-Dec-17 0:26am

Add a Solution

Comments

Jochen Arndt 12-Dec-17 3:41am

Where is CB defined?

It must be a member of your view class. If so, ON_BN_CLICKED() should work provided that the button has not been disabled meanwhile.

Check also if the button was successfully created (Create returns TRUE).

tiwal 12-Dec-17 4:56am

The CButton is a private member of my CView-derived class... I can see the button on the view and click it , but the event handler is not called.

Jochen Arndt 12-Dec-17 5:15am

What is the base class of your CMFC_csv2hstView (e.g. CEditView, CListView)?

tiwal 12-Dec-17 5:34am

It's Cview .

Jochen Arndt 12-Dec-17 5:55am

So a plain CView. As already said, it should work.

What you should check too:
- CMFC_csv2hstView::OnButton should be declared as afx_msg
- Ensure that the button ID is unique (not used for other controls in the same view)

To check if the message is handled, you can send it manually for testing:

SendMessage(GetSafeHwnd(), WM_COMMAND, (BN_CLICKED << 16) | 1, CB.GetSafeHwnd());

The above must be called from the view class. But it can be also called from elsewhere when passing a pointer to the view and using that for the first and last parameter (CB must be public then).

Alternatively think about using a CFormView based class where controls are defined in a template and does not need to be created in your code therefore.

tiwal 12-Dec-17 6:16am

I've been told there's a way to add the CButton by using the Wizard , but I cannot find out how ..... moreover, is here a way to make sure the CButton ID
is not already in use ?

Jochen Arndt 12-Dec-17 6:32am

See my answer: It works for me.

Use a CFormView based view to create a template where you can add the button with the wizard. There are lots of examples in the web about that topic.

tiwal 12-Dec-17 16:00pm

Ok , recreated the solution deriving the view from a CFormView . Now, how can I add a CButton using the Wizard ? Should I select Project|Class Wizard ?

Jochen Arndt 13-Dec-17 2:59am

You have to create a dialag template that is loaded by the form view (usually in the constructor of your derived class).
See the CFormView class documentation and related links or search the web for a tutorial.

tiwal 13-Dec-17 4:45am

Well I didn't create the dialog template but I realized that putting a CButton directly on the CFormView, the BN_CLICKED event is correctly propagated and I can handle it. It' s kind of strange that the same thing cannot be done using a Cview .

Jochen Arndt 13-Dec-17 4:57am

It can be done as shown in my solution. I created a new CView based project, added the code shown in my solution, and it works as expected.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Jochen Arndt · Answer 1 · 2017-12-12T00:26:00

I have just tested it with a new MFC application and it works as expected:

C++

// ViewTestView.h
class CViewTestView : public CView
{
    // ...
protected:
    CButton m_button;
    DECLARE_MESSAGE_MAP()
    afx_msg void OnButton();
};

C++

// ViewTestView.cpp
BEGIN_MESSAGE_MAP(CViewTestView, CView)
	// ...
	ON_BN_CLICKED(1, &CViewTestView::OnButton)
END_MESSAGE_MAP()

// ...

void CViewTestView::OnInitialUpdate()
{
    CView::OnInitialUpdate();
    
    m_button.Create(_T("Hello"), WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON, 
        CRect(100, 100, 250,250), this, 1);
}

void CViewTestView::OnButton()
{
    AfxMessageBox(_T("Button activated"));
}