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Thank you,
But my compiler have not found comutils.h . I am using Visual Studio 6.0, should I install any extension pack?
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I think it's comutil without the s. You should google _bstr_t for full info on it. You may need a platform SDK.
Christian Graus - Microsoft MVP - C++
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Hi,
COM implements two bytes per character method. You have to convert vtProp.bstrVal to a ANSI string.
For that you can use wcstombs() function.
Then you can do the comparision with the ANSI string that you have converted and the actual char[30] string you have.
" Action without vision is only passing time,
Vision without action is merely day dreaming,
But vision with action can change the world "
- Words from Nelson Mandela
Thanks & Regards,
Gopalakrishnan
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Could you give me example about how to use wcstombs()? I have made some try, but not succeded. Thank you
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Hi,
I am using CSocket class to connect between two PC and everything works fine.
However, when the other PC is power cycled, it's IP address is changing and then I'm lost of course.
Is there any way to use the MAC address of the other PC in any class that MFC offers ?
Thanks,
Shay
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The short answer is no - MFC needs the IP address. However, this problem is not new, and there are many pieces of software and services that might be able to help (take a look at DynIP for a starter)
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Thanks for the reply but this may be a bit risky to the end user.
So...
Are all the file swap services and chats like messenger etc. work only via a central server that facilitate the connection ?
Shay
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Yes, they generally all uses some sort of central server. Problem is that you can't use MAC outside your LAN network segment. Outside of this scope even the MAC address is different (see ARP for details). For connecting over tcp/ip or udp/ip you always need a IP address.
You can consider using udp broadcasts in your design - newly started application can send udp broadcast (I'm here and my address is ...) to all interesting parties. But usage of broadcasts are usually limited by the network architecture - usually up to the nearest router.
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The UDP broadcat is a nice concept, but I am connecting to PCs overseas so as you said, it will not go beyond the router.
thanks for the info.
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Hi all,
I'm trying to figure out how to control the size of a CView-derived window during a cascade operation (i.e. when the Cascade menu item in the View menu of a MFC-based MDI app is selected). I've looked into having my CView override various message handlers( WM_WINDOWPOSCHANGING, WM_GETMINMAXINFO, WM_NCCALCSIZE, and WM_WINDOWPOSCHANGED), but none of those messages seem to contain enough information for my CView to know whether it is being cascaded, or just resized in another way( maximized, restored, resized by the user, etc.).
Do I need to look into overriding the way an MFC app handles the Cascade command, and if so where would I start on that?
Any advice or suggestions greatly appreciated.
Cheers,
Pete
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Hello
Can someone help me with some code.
I'm try to get some info from a ini file and get it in a variable
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I am a little fuzzy on this concept of subclassing. I have derived my own control (derived from CEdit). I am able to utilize all of the messages common to CEdit doing this. I have seen other examples of code where the function SubClassWindow (not necessarily with a CEdit) is used by itself and also in addition to a derived class. What's the difference? When should one be used with/instead of the other. Seems both methods are doing the same thing.
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Hello...
mx483 wrote:
What's the difference?
Nothing... In front of the subclassing concept...
It's only a difference of the design concept...
I believe you have read two different solutions of subclassing, the first "used by itself" in the good old c style without inhertance and the other one in c++ with oo aspects...
 Best regards...
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There is one "subclassing" meaning in the usual class derivation: if class A derives from B, then A is a subclass of B.
The meaning of "sublassing" in methods like SubclassWindow is different. It refers to the act of changing the function that processes the messages directed to a given window (its window proc) to the one you want.
--
jlr
http://jlamas.blogspot.com/[^]
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I believe those messages are being captured when you derive a class from another class. So would the real difference be that using the derivation method you are able to add your own functions and implementation rather than just capture messages using the SubClassWindow function?
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Hi,
I'm trying to write a control that contains lots of child controls, and allows you to scroll them up and down. This would be very much like how CFormView works, except based on CWnd, not on CView. Can anyone give me a rough outline of the mechanism which CScrollView uses to draw the child controls at different locations as you pan around without moving those child windows?
Joel Holdsworth
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Thanks man. That's a massive help!
Joel Holdsworth
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I was designing the database part of a module to be developed in C++. Let me explain the scenario.
I have to access 4 different databases which are not related in any way. So I created 4 classes that holds the business logic to manipulte each of the databases. Then I thought of creating a database access class for each of the dbs to implement the data access code using ADO, so that the business logic class can call the public functions of these classes to get things done. Then I found that the Connection object is common for all the 4 classes, also there are a few methods that are common, like the OpenDatabase, CloseDatabase, IsOpen, GetProviderError etc etc. So I created a base class for that.
Now I have two options, I can either derive the 4 data access classes from the base, or I can contain a member of the base in each one of the 4. Remember, I need all the functionalities implemented in the base class as such in all the 4 classes that implement the business logic. It was found that most people say that we must try to go for weaker coupling if possible, that way I must go for containment. But then I will have to write stub functions to call the base object's function, which is an overhead.
I would appreciate it if somebody can give me an advice in this regard.
Thanks in advance,
Sylesh.
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Hello,
You can do different things depending on your needs. If your base class is likely too change a lot and your system is very large (it takes a lot of time to compile and link), I definitly would go for the private data member.
From a logical design point of view, the most obvious thing to do is to derive your specialized classes from the base class. This way, your small accessor functions can be inlined better and you don't have to do much additional allocations, since that adds a lot of overhead.
Remember this: containment comes at a price. Overhead is the price to pay. How much you contain depends on each scenario... for example, a widely used class should contain all the implementation details at the cost of more runtime overhead. A not so widely used class doesn't need to contain all the details.. etc..
Hope this helps 
Behind every great black man...
... is the police. - Conspiracy brother
Blog[^]
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I search to implement versioning support in MFC applications using ActiveX. I've got some ideas, but I wonder if I'm not re-inventing the wheel. So if somebody has any hint about embedded ActiveX versioning support, I would be grateful, TIA
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Surely you are not talking about VERSIONINFO.
"One must learn from the bite of the fire to leave it alone." - Native American Proverb
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Nope, it wasn't that one . I'm trying to use the "persistence support" mechanism from Activex serialization, which should manage versioning.. I hope
Thanks for your tip anyway, I might need it in the end 
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