C / C++ / MFC

Re: Mouse Wheel scrolling support for MFC application.

9-Jul-18 0:01

Hi sir,

i am working on MFC VC++ and i am very new to MFC application development. kindly please help me.

our application tool have a vertical scrollbar. it's working with the dragging.but not working with the mouse wheel. kindly please let me know what kind of code support have to give for mouse wheel.

i am using the below classes for creating the frame window.

1.class CMainFrame : public CFrameWndEx
{
.......

CMainFrame(); // main SDI frame window

...........
}
int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (!CreateToolBar())
{
TRACE0("Failed to create Ribbon bar\n");
return -1; // fail to create
}

if (!m_wndStatusBar.Create(this) )
{
TRACE0("Failed to create status bar\n");
return -1; // fail to create
}

m_wndStatusBar.AddElement(new CMFCRibbonStatusBarPane(ID_STATUSBAR_STATUS, csStatus, TRUE), csStatus);
	m_wndStatusBar.AddSeparator();
	m_wndStatusBar.AddElement(new CMFCRibbonStatusBarPane(ID_STATUSBAR_VER, csVersion, TRUE), csVersion);
	m_wndStatusBar.AddSeparator();
	m_wndStatusBar.AddElement(new CMFCRibbonStatusBarPane(ID_STATUSBAR_MEMORY, csMemory, TRUE), csMemory);
	m_wndStatusBar.AddSeparator();
	m_wndStatusBar.AddElement(new CMFCRibbonStatusBarPane(ID_STATUSBAR_SECURITY, csSecurity, TRUE), csSecurity);
	
	theApp.SetMainFrame(this);

}

kindly please let me know how to handle the mouse wheel messages and what are steps have to follow to enable this.

Jochen Arndt9-Jul-18 0:52

Jochen Arndt

9-Jul-18 0:52

The wheel scrolling has to be performed by the window which content should be scrolled by handling the WM_MOUSEWHEEL message | Microsoft Docs[^]. If that window is CWnd based, just override the OnMouseWheel() function.

I can not give more information because you did not give any information about your window. With frame based MFC applications, that are usually the CView derived classes.

Re: Mouse Wheel scrolling support for MFC application.

Member 139038189-Jul-18 19:16

Re: Mouse Wheel scrolling support for MFC application.

9-Jul-18 19:16

hi sir,

i wrote the code below, the code is hitting whenever my mouse wheel scrolling. but the vertical scroll bar not moving.could you please give me your input please.

Header file:

class CMainFrame : public CFrameWndEx
{
protected: // create from serialization only
CMainFrame();
DECLARE_DYNCREATE(CMainFrame)
public:
afx_msg BOOL OnMouseWheel(UINT nFlags, short zDelta, CPoint pt);

};
source file :

IMPLEMENT_DYNCREATE(CMainFrame, CFrameWndEx)
BEGIN_MESSAGE_MAP(CMainFrame, CFrameWndEx)
ON_WM_MOUSEWHEEL()
END_MESSAGE_MAP()

BOOL CMainFrame::OnMouseWheel(UINT fFlags, short zDelta, CPoint point)
{
TRACE0("in CMainFrame:: OnMouseWheel function");
return CWnd :: OnMouseWheel(fFlags, zDelta, point);
}

here CMainFrame is derived from CFrameWndEx, CFrameWndEx id derived from the CFrameWnd, CFrameWnd class is derived from the CWnd.

could you please help me if did any wrong.

Victor Nijegorodov9-Jul-18 20:37

Victor Nijegorodov

9-Jul-18 20:37

Member 13903818 wrote:
here CMainFrame is derived from CFrameWndEx, CFrameWndEx id derived from the CFrameWnd, CFrameWnd class is derived from the CWnd.

But do your application also have one or more Views (CView/CScrollView/CForView/... derived classes)?

Re: Mouse Wheel scrolling support for MFC application.

Member 139038189-Jul-18 21:04

Re: Mouse Wheel scrolling support for MFC application.

9-Jul-18 21:04

yes .....

(class CFormView : public CScrollView

class CScrollView : public CView)

in our application we are deriving the class from the CView like below.

class CCommonEDM_AVitarView : public CView

in above derived call i have handled the OnMouseWheel function. but it's not hitting the code while scrolling the mouse wheel.

code :
Header file:

class CCommonEDM_AVitarView : public CView
{
protected: // create from serialization only
CCommonEDM_AVitarView();
DECLARE_DYNCREATE(CCommonEDM_AVitarView)
public:
afx_msg BOOL OnMouseWheel(UINT nFlags, short zDelta, CPoint pt);

};
source file :

IMPLEMENT_DYNCREATE(CCommonEDM_AVitarView, CView)
BEGIN_MESSAGE_MAP(CCommonEDM_AVitarView, CView)
ON_WM_MOUSEWHEEL()
END_MESSAGE_MAP()

BOOL CCommonEDM_AVitarView::OnMouseWheel(UINT fFlags, short zDelta, CPoint point)
{
TRACE0("in CCommonEDM_AVitarView:: OnMouseWheel function");
return CView :: OnMouseWheel(fFlags, zDelta, point);
}

i am not understanding how internal child windows are working with mouse wheel scrolling. but main window is not working..

Jochen Arndt10-Jul-18 0:10

Jochen Arndt

10-Jul-18 0:10

The MFC document - view concept is a little bit complicated regarding the parent and child windows and their interaction.

But the message is sent to the control / window that has the focus. If your view contains controls then one of them probably has the focus and gets the message.

It is still unclear to which window your scroll bars belong. If they are for the view: why is your view not CScrollView based? If your view contains a single control: handle the message there.

Re: Mouse Wheel scrolling support for MFC application.

Member 1390381810-Jul-18 22:50

Re: Mouse Wheel scrolling support for MFC application.

10-Jul-18 22:50

Hello sir,

i have written the below code for my each child frame. this class is derived from the CScrollView. my mouse wheel is working fine for each individual window class. but i am trying to implement same support from my main window class.but mouse wheel is not working. could you please give me your valuable inputs.

My intention is instead of writing mouse wheel code for all the child class. if i implement mouse wheel function for my main frame. i would have been worth to all child classes.

my individual window class code :
mouse while is working with below code with below class..
Header file:

class CAboutView : public CFormView
{
-----------
afx_msg BOOL OnMouseWheel(UINT nFlags, short zDelta, CPoint pt);
}

Source file :

BEGIN_MESSAGE_MAP(CAboutView, CFormView)
//ON_WM_MOUSEWHEEL()
END_MESSAGE_MAP()

BOOL CAboutView::OnMouseWheel(UINT nFlags, short zDelta, CPoint pt)
{
return DoMouseWheel(nFlags, zDelta, pt);
}

This is my main frame:

with the below code my mouse wheel not working.
Header file :

class CMainFrame : public CFrameWndEx
{
-----------
afx_msg BOOL OnMouseWheel(UINT nFlags, short zDelta, CPoint pt);
}

Source file :

BEGIN_MESSAGE_MAP(CMainFrame, CFrameWndEx)
ON_WM_MOUSEWHEEL()
END_MESSAGE_MAP()

BOOL CMainFrame::OnMouseWheel(UINT fFlags, short zDelta, CPoint point)
{
CScrollView *wnd = NULL;
BOOL mValue;

mValue = wnd->DoMouseWheel(fFlags, zDelta, point);

return mValue;
}

Jochen Arndt10-Jul-18 23:10

Jochen Arndt

10-Jul-18 23:10

It is still unclear for which window you want to handle the scrolling.

If it is working in the views, all should be fine. Because the views show the content which might be scrolled.

The frame windows are parents of the views providing the frame and the caption bar. They did not know about the content of the client area (the view) and can therefore not know how to scroll the content.

I suggest to read about about the MFC document view architecture. Some links:
Document-View Architecture[^]
Multiple Document Types, Views, and Frame Windows[^]
Frame Windows[^]
Relationships Among MFC Objects[^]

Object pointer as method argument

_Flaviu8-Jul-18 0:43

_Flaviu

8-Jul-18 0:43

I have a CData derived from CObject. In my CDocument, I have a CMap, with key as int, and values as CData*.

In a CMyDocument method I have:

C++

void CMyDocument::GetData(int nItemData, CData* pData/* = NULL*/)
{
	m_MapData.Lookup(nItemData, pData);
	TRACE("Inside doc method: pData is not NULL: %d\n", NULL != pData);
}

and in my CMyView:

int nItemData = 1;
CData* pData = NULL;
GetDocument()->GetData(nItemData, pData));
TRACE("In MyView: pData is not NULL: %d\n", NULL != pData);

and here is the result:

Inside doc method: pData is not NULL: 1
In MyView: pData is not NULL: 0

Why inside CMyDocument I have a valid pData, but outside not ?

modified 8-Jul-18 10:17am.

Richard MacCutchan8-Jul-18 7:23

8-Jul-18 7:23

In case 1 you have not shown the value of pData. In case 2 you have explicitly set its value to NULL.

_Flaviu8-Jul-18 19:57

_Flaviu

8-Jul-18 19:57

In case 1, the trace show me that pData is not NULL, and after GetData call, I set up nothing, I only display if pData is NULL or not ... but is NULL ...

Richard MacCutchan9-Jul-18 3:01

9-Jul-18 3:01

Your test does not show what you think. It shows the values that you set in pData before the call to GetData, which does not change it. You need to reread the documentation, and understand the difference between a pointer and a reference.

CPallini8-Jul-18 20:59

CPallini

8-Jul-18 20:59

Because the CData pointer is passed by value. If you need to modify the pointer then you have to pass it by reference (or use a double pointer).

MFC Static Library Project

_Flaviu9-Jul-18 5:45

_Flaviu

9-Jul-18 5:45

I used double pointer and goes perfectly. Kindly thank you all of you (including Richard)!

Richard Andrew x647-Jul-18 16:04

Richard Andrew x64

7-Jul-18 16:04

In VS 2017, is it possible to create a static library project that exports classes the same way an MFC Extension DLL does?

I know I can create a regular static library project, but how would I make it possible to use MFC classes like CString inside that project?

The difficult we do right away...
...the impossible takes slightly longer.

Re: MFC Static Library Project

Victor Nijegorodov7-Jul-18 21:48

Victor Nijegorodov

7-Jul-18 21:48

Yes. it is possible. See also mfc as static library: is option gone? - Developer Community
What problems do you have exactly?

Re: MFC Static Library Project

Richard Andrew x648-Jul-18 3:26

Richard Andrew x64

8-Jul-18 3:26

Thank you for your response!

I just figured out how to do it.

First, create a static library project, then include all of the MFC headers in the stdafx.h file.

Thanks again. Smile | :)

The difficult we do right away...
...the impossible takes slightly longer.

Using fstream with USB Serial Port

OscardelaGrouch6-Jul-18 20:53

6-Jul-18 20:53

Hello everyone,
I'm kinda new to writing application programs for a PC, a Linux one at that, so I hope this isn't a stupid question. Wink | ;)

I am rather experienced at writing C programs for Microchip PICs. I need a PC application to interface with a PIC project, it will up load information to the PIC from the PC using a pair of Wixel modules. They are basically a USB to RF or RF to Serial bridge. I have them working (one connected to the PC, one connected to the PIC) using a terminal program. I can send data back and forth just fine.
I am now trying to send and receive data using a C++ application. The sending from the PC to the PIC works just fine also. The problem I am having is getting data from the PIC to the PC Application.

This is the application code ..

#include <cstdlib>
#include <iostream>
#include <fstream>
#include <sstream>

using namespace std;

/*
 * 
 */
int main(int argc, char** argv)
{
    fstream COMPORT;

    char line[256];
    streamsize lim = 256;
    char c;

    COMPORT.open("/dev/ttyACM0");
    
    while(1)    // only works for first input. run again and missed one reply
    {
        if (COMPORT.is_open())
        {
            cout << "Hit <Enter> to send command, <S> to Stop .." << endl;
            cin.get(c);
            if ((c == 's' || c == 'S')) 
            {
                COMPORT.close();
                return 0;
            }
            COMPORT << "UPLOAD NEW MAP\n";
            COMPORT.getline(line, lim);
            cout << "Line =" << line;
            cout << "Response=" << c;
            cout << endl;
        }
    }
    COMPORT.close();
    return 0;
}

The PIC code, if that helps ..

void APP_Wixel_IO_Test_Tasks(void)
{
    APP_ESUART_Tasks();
    if (CmdReady == 1)
    {
        CmdReady = 0;                               // reset flag
        RXBufCnt = 0;                     // reset RX Buffer count command
        utoa(TXBuf, Cnt, 10);
        strcat(TXBuf, "\n");
        WriteESUARTDataMsg(TXBuf, strlen(RXBuf));   // send command back to ESUART
        Cnt++;                                      // increment cnt
    }
}

Basically all the PIC code does is send back the 'cnt' variable when it gets data from the PC.
The

COMPORT.getline(line, lim);

doesn't work right. The first time I run it, it kinda works, but resending the data back to the PIC gets no response ..

Hit <Enter> to send command, <S> to Stop ..

Response=4
Hit <Enter> to send command, <S> to Stop ..

Response=

Hit <Enter> to send command, <S> to Stop ..

Response=

Hit <Enter> to send command, <S> to Stop ..

Response=

Hit <Enter> to send command, <S> to Stop ..

I've tried everything I can think of. Like I said, data out

COMPORT << "UPLOAD NEW MAP\n";

works fine. Data in does not.
Thanks Wink | ;)

OtG

Richard MacCutchan6-Jul-18 23:25

6-Jul-18 23:25

C++

WriteESUARTDataMsg(TXBuf, strlen(RXBuf));

Should that not be strlen(TXBuf) ?

OscardelaGrouch7-Jul-18 6:39

7-Jul-18 6:39

Yes, it should. I changed that but I get the same response from the application ..

Response=�
Hit <Enter> to send command, <S> to Stop ..

Response=

Hit <Enter> to send command, <S> to Stop ..

Response=

Hit <Enter> to send command, <S> to Stop ..

Response=

Hit <Enter> to send command, <S> to Stop ..
^C
RUN FINISHED; Interrupt; real time: 11s; user: 0ms; system: 0ms

I am pretty sure the PIC is doing it's job and replying to the message from the application (PC) correctly.
Thanks for spotting that error.
OdlG

Richard MacCutchan7-Jul-18 6:52

7-Jul-18 6:52

I have never tried to read a serial port via a stream class. Serial ports tend to be slow, and are really character oriented. You could try just using a basic file handle and reading as many characters as you can, gradually filling a buffer until you see a newline character. I know the ifstream should work that way but ...

OscardelaGrouch7-Jul-18 6:55

7-Jul-18 6:55

Thanks for the reply. I did try using get(c); but that didn't seem to work either. I will look at that some more.
OdlG

OscardelaGrouch7-Jul-18 8:21

7-Jul-18 8:21

Any advise on how to do that?
Thanks.

Richard MacCutchan wrote:
You could try just using a basic file handle and reading as many characters as you can, gradually filling a buffer until you see a newline character