ATL/COM Question - C / C++ / MFC Discussion Boards

6-Sep-01 12:44

I'm an amateur programmer, and don't know that much about C++ and MFC. I was wonder just what exactly is MFC? What does it provide for or do for the programmer? What is it used for? Is it used for Win32 programming, or just in general? If it's used in Win32 programming, does it make the programmer's life easier? I would appreciate it if someone would try to answer all of my questions to the best of their knowledge. Thanks.

~dreadknought

Re: MFC question

Christian Graus6-Sep-01 12:56

Christian Graus

6-Sep-01 12:56

The Microsoft Foundation Classes are a set of classes that encapsulate and extend Win32, which has the net effect of making development more object oriented. For example, in Win32, you called functions to create a device context, stored the handle and then deleted it. MFC wraps those calls into a class called CDC. This is especially helpful if you have Visual Assist, because you create an object, add a dot operator and get a list of available methods, which sure beats looking through MSDN for a function you know exists but can't remember the syntax for. It is also safer because destructors can ensure an item is cleaned up, which is not the case in Win32 unless you write your own class. There are all sorts of additional classes such as CArray ( rubbish, you should use vector ) and CString ( much more useful than std::string ), right through to more complex classes that manage all sorts of things.

Your copy of VC should have come with a wall chart that maps the relationships between all the MFC classes. You'll find the majority of the code on this site uses MFC. VC wizards build all the boiler plate MFC code for you, so for example to create a window or dialog takes more work in Win32, not least because the compiler isn't writing the basic stuff for you.

That's a simplistic explanation but I hope it gives an overview.

Christian

As I learn the innermost secrets of the around me, they reward me in many ways to keep quiet.

Men with pierced ears are better prepared for marriage. They've experienced pain and bought Jewellery.

Re: Well, MFC is ....

Masaaki Onishi6-Sep-01 16:13

Masaaki Onishi

6-Sep-01 16:13

Hello, the codegurus around the world. Wink | ;)

1) What exactly is MFC?
I used to read some comment of Bill Gates about MFC.
MFC is the creation which the genius programmers of Microsoft made.

MFC consists of the basic three classes like CObject, CWnd, and the other
class not derived from CObject and CWnd, and some classes are derived from
CObject and CWnd.
However, if we read the source code of these classes, we notice that MFC is wrapped by the Widnows API.

2) What does it provide for or do for the programmer?
If we made some GUI application, we at once understand that MFC makes us save the code lines and maintain the code easily.

Basically, Window 32 programming and MFC relation are almost same as C and C++. However, if we make some advanced programming like Network, Window hook,
and the other, we need both MFC and Windows API.

MFC is a powerful class for GUI application, but we also need the knowledge
of Windows API.

Good luck. Blush | :O

Have a nice day!

-Masaaki Onishi-

Re: Well, MFC is ....

Christian Graus6-Sep-01 16:31

Christian Graus

6-Sep-01 16:31

MFC consists of the basic three classes like CObject, CWnd, and the other
class not derived from CObject and CWnd, and some classes are derived from
CObject and CWnd.
However, if we read the source code of these classes, we notice that MFC is wrapped by the Widnows API.

Actually CWnd is derived from CCmdTarget, which is derived from CObject. So the majority of MFC classes derive from CObject, but there is a reasonable size group that does not. Serialisation is one reason to derive your own classes from CObject.

2) What does it provide for or do for the programmer?
If we made some GUI application, we at once understand that MFC makes us save the code lines and maintain the code easily.

Agreed - couldn't have said it better ;0)

Basically, Window 32 programming and MFC relation are almost same as C and C++. However, if we make some advanced programming like Network, Window hook,
and the other, we need both MFC and Windows API.

My main reason for replying - I'm afraid this is incorrect. If you look up Window hook in the MSDN, the top two matches are for Windows hooks in Win32. I'd also be amazed if you couldn't write network code without MFC. Given that we're given the MFC source the worst case for someone unable to use MFC for whatever reason is a trip to the source to see how they do it.

MFC is a powerful class for GUI application, but we also need the knowledge
of Windows API.

Again, could't agree more. I don't use MFC anymore, and I'm enjoying learning life without it. Wink | ;)

Christian

As I learn the innermost secrets of the around me, they reward me in many ways to keep quiet.

Men with pierced ears are better prepared for marriage. They've experienced pain and bought Jewellery.

MFC Implementation and SourceSafe

ArchV6-Sep-01 12:03

ArchV

6-Sep-01 12:03

I'm writing an MFC app and I want to access, check out, check in, stuff from a SourceSafe database. Could someone give me pointers or links to a description of how this is done? Even better would be sample code Smile | :)

Everything I've ever found about SourceSafe is how to use it in Visual Studio and not actually how to implement interface to it in a program.

Thanks

===================
Eric "ArchV" Fowler
Ritual Entertainment

Re: MFC Implementation and SourceSafe

Cathy6-Sep-01 12:07

Cathy

6-Sep-01 12:07

Look on the Microsoft website for something called Repository.

Re: MFC Implementation and SourceSafe

Not Active6-Sep-01 13:47

Not Active

6-Sep-01 13:47

You can start here, HOWTO: Open a SourceSafe Database with OLE Automation in C++. Although it was written with VB in mind this article may be useful also, Visual SourceSafe 6.0 Automation

ATL/COM Question

Bret Faller6-Sep-01 9:56

Bret Faller

6-Sep-01 9:56

Hello,

I am creating a COM DLL which is like the Outlook Object Model. I have an Application Interface/Coclass etc etc. My question is...how can I have two functions that do the same thing but have different calling methods depending on if you are using VB or VC++? Here's an example... if you look at the _Namespace interface in MSOUTL9.olb type library there is a function:

HRESULT GetDefaultFolder([in] OlDefaultFolders FolderType,
[out, retval] MAPIFolder** Folder);

if you then look at the coclass Namespace it has a function:

MAPIFolder* GetDefaultFolder([in] OlDefaultFolders FolderType);

they both have the same id and helpstring but if you use VC++ you have to call the first one, and in VB the second (due to VB not using Interfaces and using coclasses instead) but how can I create a function like that? I can only create one function with that id or else VC++ complains. Any help is GREATLY appreciated.

Bret Faller
Odyssey Computing, Inc.

Re: ATL/COM Question

Not Active6-Sep-01 10:36

Not Active

6-Sep-01 10:36

I think you are a little confused there is only one method here.
As you said it is defined in the IDL as

<br />
HRESULT GetDefaultFolder([in] OlDefaultFolders FolderType, [out, retval] MAPIFolder** Folder);

However in the coclass it is
MAPIFolder* GetDefaultFolder([in] OlDefaultFolders FolderType);

VB uses it somthing like this

Dim MFolder as MAPIFolder<br />
Set MFolder = GetDefaultFolder(...)

On the other hand in C++ it is used such as

<br />
MAPIFolder* pMFolder;<br />
HRESULT hr = GetDefaultFolder(... ,&pMFolder);<br />

The trick is the [out,retval] in the IDL definition. VB does not return HRESULT like C++ so this says that this parameter will be returned instead. The out part tells C++ that this parameter will be outgoing.

Clear it up for you?

Re: ATL/COM Question

Bret Faller6-Sep-01 11:47

Bret Faller

6-Sep-01 11:47

Very nice clarification. Thank you very much for your response.

Bret Faller
Odyssey Computing, Inc.

DebugActiveProcess

Steve The Plant6-Sep-01 9:52

Steve The Plant

6-Sep-01 9:52

Hey!

In my program, I'm enumerating the processes in Windows and
I want to be able to call DebugActiveProcess on one of them so
I can capture it's OutputDebugStrings(). But calling
DebugActiveProcess() doesn't seem to work, even if I have
the right process ID. I'm working in both Win98 and 2k. If
I call GetLastError(), in 98 I get an "invalid parameter" (#87)
error message. In 2K, I get an "access denied" error message.
What am I missing?

Steve The Plant

Re: DebugActiveProcess

Steve The Plant6-Sep-01 10:34

Steve The Plant

6-Sep-01 10:34

I just figured out what I did wrong. I was trying to attach a
debugger to a process that already had a debugger attached to
it. I was trying to attach it to a program that was run in
debug mode in VC (ie hitting F5 to run it). Of course, since
it already had a debugger I couldn't attach mine.

So now I know.

Steve The Plant

Simple variable question

6-Sep-01 7:52

I have created a Dialog-based app.

In the header-file I defined a variable CStringArray m_filearray;

If I now open a new dialog using DoModal() I want the dialog to be able to access the CStringArray defined in the "main" dialog.

How can I do this?

Re: Simple variable question

Ravi Bhavnani6-Sep-01 8:12

Ravi Bhavnani

6-Sep-01 8:12

Pass a pointer to m_filearray to the new dialog. The new dialog should have a protected member CStringArray* pStringArray that you can set via a setStringArray() method. Be sure to initialize pStringArray to NULL in the dialog's constructor and assert that it's not NULL before you reference it.

/ravi

"There is always one more bug..."
http://www.ravib.com
ravib@ravib.com

Re: Simple variable question

6-Sep-01 8:33

Could you please give an example what I have to do exactly?

I have added a protected CStringArray *m_pFileList to the second dialog and initialized it to NULL.
What do I need to do next?

thanks in advance Smile | :)

Re: Simple variable question

Christian Graus6-Sep-01 12:57

Christian Graus

6-Sep-01 12:57

Add a method called SetStringArray that takes a pointer to a CStringArray and pass in the address of the array.

Christian

As I learn the innermost secrets of the around me, they reward me in many ways to keep quiet.

Men with pierced ears are better prepared for marriage. They've experienced pain and bought Jewellery.

Using CFormView with CSlpitterWnd

6-Sep-01 7:49

Hi,

I have a SplitterWnd with two panes. In one I have a CFormView and the other is a CView. I'd like to position the (vertical) splitter bar so that it's equal to the width of the FormView when the splitter is created. I'd also like the positioning to be dynamic, so if I edit the CFormView dialog, making it wider, the splitter will be created in the proper location.

Also, I'd like to know what message is fired before the scrollbars are displayed in the FormView. In certain cases, I'd like to prevent the horizontal scroll bar from appearing by shifting the vertical scrollbar to the right. I do this now by checking the size of the window as it's being resized and then shifting the scrollbar, but it's very sloppy because the scrollbars are displayed before I trap the resize message.

Thanks for any help you can offer.

Tom

Re: Using CFormView with CSlpitterWnd

Not Active6-Sep-01 10:48

Not Active

6-Sep-01 10:48

I don't believe there is a message generated when a scroll bar is about to be displayed.

Re: Using CFormView with CSlpitterWnd

7-Sep-01 7:29

Any ideas on how to get the size of the dialog template at runtime so I can locate the splitterbar to align with the width of the dialog template?

Re: Using CFormView with CSlpitterWnd

Brad Bruce7-Sep-01 15:09

Brad Bruce

7-Sep-01 15:09

Create a static frame the desired size of the dialog and use that as the frame size.

Set ODBC DSN when setup.

6-Sep-01 7:45

I am going to distribute my database-based C++ application. But I don't know how to set ODBC DSN when setup. Is there any one can tell me that, or is there any installer support that function?

Thanks,

Re: Set ODBC DSN when setup.

Not Active6-Sep-01 11:05

Not Active

6-Sep-01 11:05

If your using Installshield there is a wizard to set ODBC data sources, or you can set it in the registry under HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBC.INI

Thanks

6-Sep-01 12:37

Thanks

Mini School Project

Ramzirex6-Sep-01 5:17

Ramzirex

6-Sep-01 5:17

Can anyone help me in my school project?I'm a beginner at microsoft visual c++ any need help in doing a program.I would appreciate it if anyone is willing to help me doing it.Thanks alot!
Roll eyes | :rolleyes:

Re: Mini School Project

Carlos Antollini6-Sep-01 5:33

Carlos Antollini

6-Sep-01 5:33

Code Project is not a place for make your HomeWork, but We can help you making the Alpha Version, of your Project.

Cheers!!!! Big Grin | :-D

Carlos Antollini.

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