C / C++ / MFC

Re: How to capturing mouse movement with a derived base class

4-Oct-02 5:51

Check the BEGIN_MESSAGE_MAP macros in .cpp files. Probably Your_Button1 goes straight to CButton (not to Your_Button) when handling Windows messages - it has CButton as 2nd macro argument and should have Your_Button.

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

work_to_live4-Oct-02 7:07

work_to_live

4-Oct-02 7:07

Thanks, that did the trick. Guess you can tell I'm new at this. Seemed obvious once you provided the answer. Of course, doesn't it always? Smile | :)

Thanks again for the speedy reply.

problem with CPtrArray

Tom Putzeys4-Oct-02 5:29

Tom Putzeys

4-Oct-02 5:29

Hi,

Can anyone explain the following problem, to do with CArray and CPtrArray?

My member variables are:

CArray<CMyClass,CMyClass> m_objects;
CPtrArray m_pointers;

I try to initialize them like this:

for(int i = 0; i < 5; i++){
   m_objects.Add(CMyClass());
   m_objects[i].m_nMember = i;
   m_pointers.Add((void*) &m_objects[i]);
}

In my paint function, I just loop through the pointers, cast them and output the value of m_nMember. Like this:

for(int i = 0; i < m_pointers.GetSize(); i++){
   int value = ((CMyClass*) m_pointers.GetAt(i))->m_nMember;
   //draw value to the screen
}

I'd expect the output to be: 0 1 2 3 4, but it's not; 1 to 4 are always correct, but the first value is always nonsensical.

I was able to solve the problem by using a different initialization:

for(int i = 0; i < 5; i++){
   m_objects.Add(CMyClass());
   m_objects[i].m_nMember = i;
}

m_pointers.SetSize(m_objects.GetSize());

for(i = 0; i < m_objects.GetSize(); i++){
   m_pointers.SetAt(i, (void*) &m_objects[i]);
}

But still I would like to understand why the first approach doesn't work. Anyone have a clue? Is it a bug or something?

Thanks,

Tom

Re: problem with CPtrArray

Pavel Klocek4-Oct-02 6:34

Pavel Klocek

4-Oct-02 6:34

The CArray is a dynamic array. If you add data to it and the currently allocated memory is already full, the storage is reallocated and the data are copied to the new memory (using copy constructors for classes).

Because you have not specified the length of the array in advance, the initial length was only 1 and the array was reallocated before inserting the second item - so your first pointer points to nowhere => it's wrong to use pointers to container data this way.

Also it is good practice to allocate the array using SetSize(), if you know the required size in advance.

Pavel
Sonork 100.15206

Stored Procedures in DAO

SamirSood4-Oct-02 5:22

SamirSood

4-Oct-02 5:22

Can Anyone tell me how to call Stored Procedures of SQL Server in DAO

Samir Sood

find remote machine mac address

Anonymous4-Oct-02 5:23

Anonymous

4-Oct-02 5:23

I need to find the mac address of all the machines in the network. I already know the ip address from the DNS table. Can someone tell me how to use the ip address to find its corresponding mac address? Thank you.

Re: find remote machine mac address

Andreas Saurwein4-Oct-02 5:37

Andreas Saurwein

4-Oct-02 5:37

sorry, VB has to do it Smile | :)

http://www.mvps.org/vbnet/index.html?code/network/macaddress.htm[^]

...if you're under 8 or younger. Chris Maunder, the Lounge

Re: find remote machine mac address

Scott H. Settlemier4-Oct-02 5:51

Scott H. Settlemier

4-Oct-02 5:51

You can use the ARP utility.

ISO and UDF source?

chen4-Oct-02 5:16

chen

4-Oct-02 5:16

HI,

Did you have seen some materials or VC++ source code about
CD image file system: ISO or udf ?

Any information or ideas?

Thanks a lot!

chen

Re: ISO and UDF source?

Andreas Saurwein4-Oct-02 5:57

Andreas Saurwein

4-Oct-02 5:57

Did you bother to search codeproject? Maybe this[^] helps

...if you're under 8 or younger. Chris Maunder, the Lounge

how to simulate an animal's random movement

wangnanjing4-Oct-02 5:10

wangnanjing

4-Oct-02 5:10

Hello ,everyone,

I want to simulate an animal's movement on a specified terrain.
According to the terrain's changement,I can also change the
animal's moving direction and velocity.
Besides,the animal behaves in random on the rerrain.

In the first step.we can just take the animal as one point.

Anyone has any good idea or code example for me?

thanks a lot.

wang

Scott H. Settlemier4-Oct-02 5:20

Scott H. Settlemier

4-Oct-02 5:20

what sort of animals?

flocking behavior? herd movement?
slugs are always nice.
cats would probably be kinda hard-- they go all over.

wangnanjing4-Oct-02 5:19

wangnanjing

4-Oct-02 5:19

hi,

I think in the first step,we can simulate a slug's random movement.
All your advices are good.
Do you have any idea?

thank you so much for your quick reply.

weiwei

wang

Scott H. Settlemier4-Oct-02 5:43

Scott H. Settlemier

4-Oct-02 5:43

The majority of stuff I've seen is heuristic mitigation of plain ol' random walks. (such as modeling ant trails for finding optimum paths instead of using simulated annealing.)

Maybe you are more interested in the AI stuff though that focuses on goals and desired behavior. (The random walk stuff is usually used to further some other goal than modeling the qualitative behavior of an animal.)

Game developer resources/books are probably what you want right?

Or are you just trying to model animal movement as part of an ecological simulation? (that's where the random walk stuff is employed)

In any case, Google is your friend. Wink | ;)

Andreas Saurwein4-Oct-02 5:30

Andreas Saurwein

4-Oct-02 5:30

take a look at the Terrarium source over at www.gotdotnet.com. for a better approach you will need to dig into some more advanced studies. look here [^]

...if you're under 8 or younger. Chris Maunder, the Lounge

CDialogBar

lucy4-Oct-02 5:05

4-Oct-02 5:05

I created a dialog template using the resource editor, I've change its style to Child and No Border. Now I want to create a class for this template, which inherit from CDialogBar.

The problem is: when use ClassWizard to do this, there is no CDialogBar in the selection for the base class. If I select CDialog there and replace CDialog using CDialogBar manually, later when I want to add any function to my dialogbar class, class wizard will pop those for CDialog.

What do you do? Thanks a lot!

Tomasz Sowinski4-Oct-02 5:16

4-Oct-02 5:16

Probably there are 'CDialog' references in MFC-generated code (message map etc). Also, you can delete .clw file - it will be recreated by ClassWizard.

What exactly do you want to override in CYourDialogBar?

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

lucy4-Oct-02 5:36

4-Oct-02 5:36

For example, I have an edit box in my dialog bar. Some time ago, I have created an edit class which will allow the edit box to accept numbers only.

Now, I want to subclass the CEdit using my CNumEdit.

When the edit box is in a dialog, I do this in OnInitDialog(). Which is what classwizard will point me to. But instead, I should do it in Create() since CDialogBar don't have OnInitDialog().

Maybe I should use the "Class Info" tab of the class Wizard to select "Window" message only, since I know CDialogBar is not dialog, but a CWnd instead.

Tomasz Sowinski4-Oct-02 5:48

4-Oct-02 5:48

I belive CDialogBar will get WM_INITDIALOG. Lack of entry in message list in ClassWizard is just a VC IDE problem. You can always add the entry to message map manually - just have a look at some CDialog-derived class in your program.

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

lucy4-Oct-02 5:46

4-Oct-02 5:46

no, it doesn't. WTF | :WTF:

When I compiled the code, VC++ will complain that OnInitDialog is not a member of CDialogBar, and it leads me to see the declaration. It is not there indeed. Eek! | :eek:

Tomasz Sowinski4-Oct-02 5:59

4-Oct-02 5:59

So just don't call CDialogBar::OnInitDialog in CYourDlgBar::OnInitDialog Smile | :)

However, if all you need is edit subclassing, just provide your own Create. Catching WM_INITDIALOG doesn't make sense if all you need is this single operation.

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

lucy4-Oct-02 5:57

4-Oct-02 5:57

I wonder what you usually do when you want a dialog bar in your application? How do you create the class when you are done with the dialog template? Confused | :confused:

Tomasz Sowinski4-Oct-02 6:20

4-Oct-02 6:20

lucy wrote:
How do you create the class when you are done with the dialog template?

I'd just create the class without IDE help. Or - I'd select 'generic CWnd' and replace CWnd with CDialogBar later in .h and .cpp.

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

lucy4-Oct-02 6:17