C / C++ / MFC

13-Nov-01 4:34

I have a workspace consisting of five projects. Let's call them Project A through E. The structure I'm aiming for is the following:

  A
 / \
B  C
  / \
 D   E

I've updated the dependencies so that A is dependent of B and C, and C is dependent of D and E.

Project A is a regular application while B through E are static libraries providing functionality to the application.

My problem is that I have a couple of classes with identical names in the different projects. The classes aren't identical but play a similiar role in the different projects. When compiling I get warnings about the classes already being defined and that the second definition is ignored.

Since I'm still relatively new to VC++ I'm not sure if my approach is the right one. Maybe I should try another structure, but this is the one that feels most intuitive because of the way my projects are related.

Maybe I'm just not including my libraries correctly? Or is the problem that I have conflicting class names? Should I rename the classes within the projects, or is it possible to just add some sort of namespaces?

I would much appreciate some pointers to what I might be doing wrong. Examples of project settings and such.

Thanks in advance!

Michael P Butler13-Nov-01 4:41

Michael P Butler

13-Nov-01 4:41

I'm a big fan of using namespace. I have a number of libraries that I have similiar named classes and I use namespace a lot. It helps too when I use a third party library which has a class named the same as one of mine.

Michael Smile | :)

Jimmy Ehrnström13-Nov-01 4:51

13-Nov-01 4:51

Namespaces will most likely solve my problem so I'll give them a try. Unfortunately I'm not very familiar with them, but I'll go namespace hunting in the MSDN. Cool | :cool:

Thanks for your time!

Michael P Butler13-Nov-01 4:58

Michael P Butler

13-Nov-01 4:58

quiet simple

in your class .h

namespace yournamespacename
{
  class CMyClass
  {
  };
}

To use it, yournamespacename::CMyClass myclass;

Michael Smile | :)

Jimmy Ehrnström13-Nov-01 5:10

13-Nov-01 5:10

Ok, but does this mean that I'll have to specify the namespace for each and every class in a library, or is there a way to specify a namespace for the whole library at once?

Paolo Messina13-Nov-01 7:03

Paolo Messina

13-Nov-01 7:03

See the keyword: using namespace ...

You can see an example when you create a new "Win32 console application" project that supports MFC, right before _tmain().

I'm not an expert of namespaces, though, just know what to look for Wink | ;)

Paolo

------
"airplane is cool, but space shuttle is even better" (J. Kaczorowski)

Jimmy Ehrnström13-Nov-01 20:26

13-Nov-01 20:26

Yes I found the keyword and it will probably come in handy when I want to use my libraries.

But what I would like to avoid is to declare the same namespace several times, once for each class, in my library and instead declare a namespace for the whole library at once. I have no idea if this is possible though?

Paolo Messina14-Nov-01 7:02

Paolo Messina

14-Nov-01 7:02

Have you tried to do:

namespace yournamespacename
{
#include "mylibrary.h"
}

I read somwhere that you can do something like that, but never tried.

Paolo

------
"airplane is cool, but space shuttle is even better" (J. Kaczorowski)

Jimmy Ehrnström15-Nov-01 1:04

15-Nov-01 1:04

Using this method I lost the warnings about classes already being defined. But I still get errors when compiling. This is how my code looks like now:

namespace LibA {
  #include "LibraryA.h"
}
namespace LibB {
  #include "LibraryB.h"
}
.
.
.
LibA::MyClass myClassInLibraryA;
LibB::MyClass myClassInLibraryB

When compiling this code I get several LNK2001 errors. So it seems the compiler can't resolve the namespace after all. It makes no difference if I try "using namespace LibA" instead.

Am I doing something wrong when trying to access my libraries?

Maybe I have to modify my code, so that I specify the namespace for every class, after all. Frown | :(

Jimmy Ehrnström15-Nov-01 1:41

Error when INSERT in Excel db

15-Nov-01 1:41

Some experimenting seems to reveal that my problem is happening because I try to use two libraries (with name collisions) from another library. I created a new project where my two libraries are used by a regular application, and that seems to work.

I guess I'll do some redesigning so that I don't need multiple library levels in my program.

Thanks for all your help!

XAlien13-Nov-01 4:25

XAlien

13-Nov-01 4:25

Hi all,
I have a strange problem, I have inserted a lot of row in a sheet excel using sql statement "INSERT INTO tabname (A,B) VALUES ('xxx','yyy')" and all is ok.
then I open the excel file and copy and paste some row, from this moment the INSERT statement don't work! It send me a message: "impossibile espandere l'intervallo denominato" in italian, in english I think "impossible expand named interval"...
Anyone know why?
I'm sorry for my english... Blush | :O

CMonthCalCtrl and mouse messages

13-Nov-01 3:57

Is it just my feeling, or it is impossible to catch and handle double-click on MFC CMonthCalCtrl control?

I have a modal dialog which contains only this control, and I would like to close it when user double-clicks on calendar.

I've tried handling mouse messages from both dialog class and CMonthCalCtrl-derived class, but apparently control takes the capture and WM_LBUTTONDBLCLK is never generated (which is also true for NM_DBLCLK notification messages).

Thanks

Christian Graus13-Nov-01 8:57

Christian Graus

13-Nov-01 8:57

If that is the case, try SetCapture in the parent window.

Christian

After all, there's nothing wrong with an elite as long as I'm allowed to be part of it!! - Mike Burston Oct 23, 2001

adrenochrome13-Nov-01 10:54

adrenochrome

13-Nov-01 10:54

Setting capture brings many problems, starting with how to maintain it. Parent window is a modal dialog; setting capture makes it unusable.

Re: Try to use PreTranslateMessage func!

Christian Graus13-Nov-01 18:22

Christian Graus

13-Nov-01 18:22

Not at all, it DOES mean you need to pass the messages on to your child windows. It's not pretty, but if the window doesn't inform you of click messages to itself, then it may be the only solution.

Christian

After all, there's nothing wrong with an elite as long as I'm allowed to be part of it!! - Mike Burston Oct 23, 2001

Masaaki Onishi13-Nov-01 11:35

Masaaki Onishi

13-Nov-01 11:35

Hello, the codegurus around the world.;)

We can use PreTranslateMessage to capture WM_LBUTTONDBLCLK == message
and use GetFocus func to get which control is now get the input focus.

But, WM_LBUTTONDBLCLK may be a little ambigours since
one clicking the mouse is sometimes generated if we try to click the mouse twice? Cry | :((

Have a nice day!

-Masaaki Onishi-