C / C++ / MFC

1-Nov-11 11:20

Since I converted from VS6 to VS2010, I have found that lots of my dialog messages no longer work (e.g., BN_CLICKED, CBN_SELCHANGED).

I can Spy++ on the dialog and see the WM_COMMAND with the right notify code, by my dialogs handlers aren't getting the messages.

I expected some issues on upgrading, but this wasn't one of them!

Any suggestions on how to find out what is happening to my messages?

Cheers

Software_Developer1-Nov-11 11:57

Software_Developer

1-Nov-11 11:57

You could try "Create New Project from Existing Code" if the conversion is problematic.

VC++ 10 is a lot better on conformance to the standard, so you may find the VC++ 6 source code no longer compiles even when you have a working project file (a good thing). Fixing such problems up is not generally too hard.

BTW Visual C++ 2010 Express does not have MFC. To compile MFC in Visual C++ 2010 Express read THIS.

Kyudos1-Nov-11 12:19

1-Nov-11 12:19

I've done the conversion - it compiles, links and runs.

It just doesn't work.

Chuck O'Toole1-Nov-11 12:56

1-Nov-11 12:56

I converted a dozen or so projects and never had this particular problem. So I'd check the basics.

1) does the BEGIN_MESSAGE_MAP() have the proper chain of derived and parent classes.
2) does the IDCs of the controls you are expecting map properly to the controls in the dialog you are displaying? I have seen things work by accident because older versions of Visual Studio allowed duplicate IDCs in separate dialogs but the code didn't expect that. Verify then against Resource.h.
3) are controls subclassed properly with DDX (if doing that)

There are a lot of things that need to be stitched together properly for the magic to work.

Kyudos1-Nov-11 13:17

1-Nov-11 13:17

Chuck O'Toole wrote:
1) does the BEGIN_MESSAGE_MAP() have the proper chain of derived and parent
classes.

These are OK - or at least, they haven't changed.

Chuck O'Toole wrote:
2) does the IDCs of the controls you are expecting map properly to the controls
in the dialog you are displaying? I have seen things work by accident because
older versions of Visual Studio allowed duplicate IDCs in separate dialogs but
the code didn't expect that. Verify then against Resource.h.

I don't think this is it, I have no duplicate IDs.

Chuck O'Toole wrote:
3) are controls subclassed properly with DDX (if doing that)

I'm not doing this! Smile | :)

This[^] exactly describes my symptoms, but doesn't give a solution (for me anyway).

The only other relevant thing is that I moved all my resources to a DLL (for reasons of internationalisation!). But they all still have the same IDs etc.

Thoughts (and thanks!)?

Chuck O'Toole1-Nov-11 13:32

1-Nov-11 13:32

The suggestions on that forum page you referenced were pretty good. Especially the part about checking the actual .rc file to make sure all the symbols line up for the control in question.

It also suggested a place to put a breakpoint in the windows dispatch / search routine where it actually tries to match up your MESSAGE_MAP entry (IDC) with the IDC of the control that was clicked (RC file).

Lastly, and it's always a good suggestion, do a clean / complete rebuild to force a recompile of all the resource and source files to make sure everybody's using the same files. That may not have happened if you did a "convert in place" from the old to the new project.

Me, I'd do the full rebuild and the debug from the AFX dispatch to see where it's looking for MESSAGE_MAP entries and why it can't find yours.

Kyudos1-Nov-11 13:55

1-Nov-11 13:55

Thanks for your help. I have found a way to fix it - but I wonder if this is a change required by VS2010, or if something deeper is wrong.

Lets say I'm on dialog A, which is a kind of dialog B. Currently, in A.cpp:

C++

BEGIN_MESSAGE_MAP(A_Dlg, B_Dlg)
    //{{AFX_MSG_MAP(A_Dlg)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

and in B.cpp:

C++

BEGIN_MESSAGE_MAP(B_Dlg, C_Dlg)
    //{{AFX_MSG_MAP(B_Dlg)
    ON_BN_CLICKED(IDC_MYBUTTON, OnMyButton)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

This previously worked fine and allowed me to use IDC_MYBUTTON on all "B" dialogs to give me a generic B-dialog function.

If I add ON_BN_CLICKED(IDC_MYBUTTON, OnMyButton) to the A-dialog message map, the routing works. But why is this necessary? I added the function to the "B" base class so I WOULDN'T have to do this sort of thing.

Chuck O'Toole1-Nov-11 14:01

1-Nov-11 14:01

I certainly don't do it that way. But if you think of it, if the button is in the "A" dialog, then the MESSAGE_MAP for "A" should be the place for it. I don't think polymorphism applies to controls.

It may be accidental that the RTLs for the older VS didn't check "ownership" where the newer RTLs do. Might even have been a bugfix for someone complaining that what you relied on was, in fact, a bug deserving of a fix.

Anyway, you've got the root problem figured out.

Chuck O'Toole1-Nov-11 15:21

1-Nov-11 15:21

The documentation on processing message maps seems to support your concept of "virtual action routines" passing from derived window to parent/base class. So, I'd verify your hierarchy is correct first, then ask Microsoft if it's broken but I wouldn't hold up my application for a fix.

http://msdn.microsoft.com/en-us/library/6kc2tzde(v=VS.100).aspx[^]

SQL

The first argument names the class to which the message map belongs. The second argument provides a connection with the immediate base class — CView here — so the framework can search its message map, too.

The message handlers provided in a base class are thus inherited by the derived class. This is very similar to normal virtual member functions without needing to make all handler member functions virtual.

If no handler is found in any of the base-class message maps, default processing of the message is performed. If the message is a command, the framework routes it to the next command target. If it is a standard Windows message, the message is passed to the appropriate default window procedure.

Kyudos1-Nov-11 15:36

1-Nov-11 15:36

Yeah, I created a little test MFC app to check, and it works fine there! Mad | :mad:

Kyudos1-Nov-11 16:25

1-Nov-11 16:25

It gets stranger and stranger!

I was paraphrasing my code before, it's more like:

C++

BEGIN_MESSAGE_MAP(B_Dlg, C_Dlg)
    //{{AFX_MSG_MAP(B_Dlg)
    ON_BN_CLICKED(IDC_ONE, OnFunctionA)
    ON_BN_CLICKED(IDC_TWO, OnFunctionA)
    ON_BN_CLICKED(IDC_THREE, OnFunctionA)
    ON_BN_CLICKED(IDC_FOUR, OnFunctionB)
    ON_BN_CLICKED(IDC_FIVE, OnFunctionC)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

The message map IS actually working, but only for the first entry in the map! If I change the order, I can change what works and what doesn't... Confused | :confused:

Re: Where are my messages going? - *#@!ing MS!

Albert Holguin2-Nov-11 5:31

Albert Holguin

2-Nov-11 5:31

Check to make sure that the IDC_ numbers aren't messed up in the resource file. If they're somehow the same, that would cause this behavior you're seeing.

Kyudos1-Nov-11 17:08