C / C++ / MFC Discussion Boards

22-Jul-01 5:20

Could some people give me some clues as to how you come up with classes etc in your programs??

I often have problems like this one Im having now - I want to change the status bar text from somewhere in my program (I think its the view class), but to do so I need to get at the m_wndStatusBar object which is instantiated in the main frame class. How can I possibly do something like this?? A lot of the time it would make sense to write an member function and call this from the view, but as I dont have anything a CMainFrame instantited in the view then obviously in this situation this would be no use.

Another problem I also have often is this. If for instance I am designing a Contact Management system. I might have two extra classes - a CContact and a CDatabase (to encapsulate the database stuff.) I have a button in a Dialog, (or a menu handler in the view) which is supposed to fill a linked list with CContact objects then what am I best to do. As I see it there are a few ways:

1. Instantiate CPerson objects in the dialog and pass them to the database class to fill?
2. Instantiate a CDatabase object in the CContact class and make this class call methods of the database transparently - so I can do MyPerson.GetPersonDetails() and the database stuff is transparent.

There are probably many more ways to approach the above problem too. But hopefully I made clear the problems I am having- basically decididng on which classes to use, deciding which classes should contain instances of other classes, and then when I have implemented this, what is the course of action if I need some info from a class which I dont have access to.

Any help on this subject would be . appreciated, and Im sure lots of other people must have the same kind of confusion on this topic too...

Thanks,
Ben

HBITMAP AND BITMAPINFOHEADER

AJ12322-Jul-01 1:56

AJ123

22-Jul-01 1:56

Hi,

I have a HBITMAP and want to get a Bitmapinfoheader structure from it, wo i can access the width and height members.

Anyone offer me any advice.

Cheers

Richard

Re: HBITMAP AND BITMAPINFOHEADER

C^hris L^osinger22-Jul-01 3:51

C^hris L^osinger

22-Jul-01 3:51

to get a DIB from an HBITMAP you use GetDIBits. (a DIB is a BITMAPINFOHEADER followed by an image).

but if you just want the width and height, use GetObject.

[code]
BITMAP bmp;
GetObject(hBmp, sizeof(BITMAP), &bmp);
width = bmp.bmWidth; // etc.
[/code]

-c

------------------------------
Smaller Animals Software, Inc.
http://www.smalleranimals.com

What can DLL and LIB do? How to create DLL and LIB files and How can u use these back within a VC++ program?

will22-Jul-01 1:48

will

22-Jul-01 1:48

Sorry, I am a new boy to this, may anyone of u tell me the answer, please, urgent! Many thanks!

Reguards,

Confused | :confused:

will

How to make edit box not visible

nulldreamer21-Jul-01 23:52

nulldreamer

21-Jul-01 23:52

here is what I got

treeDialob dlg;
dlg.m_edit.
//is there something I can put here to make it //disappear?
dlg.DoModal();

Thanks a lot!!

Re: How to make edit box not visible

Hadi Rezaee22-Jul-01 0:07

Hadi Rezaee

22-Jul-01 0:07

Hi,
CEdit *pEdit = (CEdit *)GetDlgItem(IDC_EDIT1);
pEdit->ShowWindow(SW_HIDE);
// pEdit->EnableWindow(FALSE);

Smile | :)

My month article: Game programming by DirectX by Lan Mader.
Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

Re: Humm, is this right?

Masaaki Onishi22-Jul-01 4:28

Masaaki Onishi

22-Jul-01 4:28

Hello, the codegurus around the world. Smile | :)

CMyDialog dlg;
//We can't hide the edit box since Edit box isn't created yet.
//So, ;P &  X|
if (!dlg.m_edit.GetSafeHwnd())
   MessageBox ("Sorry this", "Test");
dlg.DoModal();

Use the code - ShowWindow in BOOL CMyDialog::OnInitDialog (),
or use the resouce editor to take off the check box of Visible in m_edit.

Have a nice day!

-Masaaki Onishi-

Re: Humm, is this right?

nulldreamer22-Jul-01 10:46

nulldreamer

22-Jul-01 10:46

Well, how do you do it then,
I want when the user clicks a certain radio button, an edit box to appear, but until the radio hasn't been clicked, to stay hidden?

Re: Well...

Masaaki Onishi22-Jul-01 12:49

Masaaki Onishi

22-Jul-01 12:49

Hello, the codegurus around the world.;)

Well, first of all, you should say clearly what you want.

I just created one radio button to show or hide the edit box.

If we open the dialog, the edit box is shown, and the radio button
title is "Hide the edit box".
If we click the radio button, the edit box disappers, and the raio button title is "Show the edit box".
After we click the radio button, the radio button is unchecked in two seconds.

// message handler if we click the radio button;
void CSlidingDlg::OnRadio1() 
{
	// Get editbox and radio button's CWnd.
	// These are the school level approach.
	// We also can use the class wizard to assign each control variable;
	CButton *rdButton = (CButton*)GetDlgItem (IDC_RADIO1);
	ASSERT(rdButton);

	CEdit *editbox = (CEdit*)GetDlgItem (IDC_EDIT1);
	ASSERT(editbox);

	// Check if the edit box is hidden or not, show if hidden;
	editbox->IsWindowVisible() ? editbox->ShowWindow (SW_HIDE) :
				editbox->ShowWindow (SW_SHOW);

	// Update the radio button caption if the radio button is hidden, title should be "Show the edit box";
	rdButton->SetWindowText (editbox->IsWindowVisible() ? "Hide the edit box" : "Show the edit box");

	Sleep (2000);
	// Uncheck the radio button since I use only one radio button to show and hide the edit box;
	rdButton->SetCheck(0);
}

Have a nice day!

-Masaaki Onishi-

Re: Humm, is this right?

Andrew Peace22-Jul-01 13:59

Andrew Peace

22-Jul-01 13:59

In the dialog resource, just untick the Visible property of the Edit control. Then, use ShowWindow(SW_SHOW) to show it again when the radio button is clicked.

> Andrew.

CStringArray

Michael Martin21-Jul-01 21:55

Michael Martin

21-Jul-01 21:55

Wondering how to determine the number of elements stored in a CStringArray. I want to get back how elements hold data not how many it's capable of holding.

If I use SetSize(10, 5) to set the initial size of the array to 10 elements and then add 7 actual elements I get the following results.

GetSize() returns 10 while GetUpperBound() returns 9, when I want to get 7 and 6 respectively.

Is this possible?

Michael Martin
Pegasystems Pty Ltd
Australia
martm@pegasystems.com
+61 413-004-018

Re: CStringArray

Anders Molin22-Jul-01 3:53

Anders Molin

22-Jul-01 3:53

I don't think a CStringArray knows how many strings you have added. It knows the size, but not how many of the pointers you actually use.

Why don't you use CStringList if you want that functionallity?

- Anders

Money talks, but all mine ever says is "Goodbye!"

Re: CStringArray

Michael Martin22-Jul-01 4:04

Michael Martin

22-Jul-01 4:04

Anders

cause I'm dumb, stupid and didn't know it existed. Now you have pointed it out to me I will look it up, but not until tomorrow. I have waited until midnight Sunday to get an answer, better get to bed if I'm going to make in it to work on time.

Once again thanks for the answer.

Michael Martin
Pegasystems Pty Ltd
Australia
martm@pegasystems.com
+61 413-004-018

Object Oriented DLL Problem

21-Jul-01 21:35

I am trying to package a reusable class library in a win32 dll
however I have run into a problem,
Class B and B2 derive from class A, heres the simplified code:
class __declspec( dllexport ) A
{
public:
A();
virtual ~A();
virtual void SomeFunc(void) = 0;
};

class __declspec( dllexport ) B : public A
{
public:
B();
virtual ~B();
void SomeFunc(void);
};

class __declspec( dllexport ) B2 : public A
{
public:
B2();
virtual ~B2();
void SomeFunc(void);
};

A::A()
{
cout << "A constructor." << endl;
}

A::~A()
{
cout << "A destructor." << endl;
}

B::B()
{
cout << "B constructor." << endl;
}

B::~B()
{
cout << "B destructor." << endl;
}

void B::SomeFunc(void)
{
cout << "B::SomeFunc()" << endl;
}

B2::B2()
{
cout << "B2 constructor." << endl;
}

B2::~B2()
{
cout << "B2 destructor." << endl;
}

void B2::SomeFunc(void)
{
cout << "B2::SomeFunc()" << endl;
}

This compiles into a DLL without any problems. However when
I attempt to use it (I have linked to the .lib and put the
.dll in the executable directory) using the following code:

#include "A.h"
#include "B.h"
#include "B2.h"

int main(void)
{
A* test = NULL;
test = new B();
test->SomeFunc();
delete test;

return 0;
}

I get the output as expected:
A constructor.
B constructor.
B::SomeFunc()
B destructor.
A destructor.

But then a nasty debug assertion failure:
Debug Asserion Failed.
File: dbgheap.c

Expression: _pFirstBlock == pHead

Oddly enough, if I comment out delete test; the assertion failure does not occur, but I dont want memory leaks in my programs. I know that converting it too a COM dll and using interfaces would problably be the best solution, however I want to first learn how to create normal dlls before I mess with making them COM compliant.

Re: Object Oriented DLL Problem

21-Jul-01 21:59

Have you tried calling delete []? Call it with the brackets and see if the same problem occurs.

Re: Object Oriented DLL Problem

Joaquín M López Muñoz22-Jul-01 5:39

Joaquín M López Muñoz

22-Jul-01 5:39

Check if the DLL is built with the same C runtime
library version as the program you're using it from
(i.e. Multithreaded or not, static ot dynamic, debug
or release). If versions differ this kind of problems
can occur

CHttpServer Class?

dark12021-Jul-01 15:54

dark120

21-Jul-01 15:54

Does anyone here know the commands for the CHttpServer and how to use it? I was just curious...

"The world doesn't care about your self esteem. The world expects you to get something done BEFORE you feel good about yourself." ~ Bill Gates

Re: CHttpServer Class?

Not Active22-Jul-01 10:25

Not Active

22-Jul-01 10:25

Try MSDN on-line

Question about Interdev

21-Jul-01 14:47

I was wondering whether Visual Interdev is itself an MFC app and if so, I was wondering what MFC classes is it derived from?

thanks Confused | :confused:

Re: Question about Interdev

Anders Molin22-Jul-01 3:57

Anders Molin

22-Jul-01 3:57

Visual C++ is a MFC application, so I guess Interdev is too...

- Anders

Money talks, but all mine ever says is "Goodbye!"

Please help me to fix a bug in Windows XP.

21-Jul-01 14:09

Hi everyone,

I hope programmers here can help me. One of my beta-testers said that he had encountered a problem. The problem is the following: Windows XP does not work. Can anyone help me to fix it? Here is the source code of Windows XP:

/*
TOP SECRET Microsoft(c) Code
Project: Redmond(tm)
Projected release-date: September 2001
*/

#include "win31.h"
#include "win95.h"
#include "win98.h"
#include "winME.h"
#include "evenmore.h"
#include "oldstuff.h"
#include "billrulz.h"
#define INSTALL = HARD

char make_prog_look_big[1600000];

void main()
{
while(!CRASHED)
{
display_copyright_message();
display_bill_rules_message();
do_nothing_loop();
if (first_time_installation)
{
make_50_megabyte_swapfile();
do_nothing_loop();
totally_screw_up_HPFS_file_system();

search_and_destroy_the_rest_of_OS/2();
hang_system();
}
write_something(anything);
display_copyright_message();
do_nothing_loop();
do_some_stuff();
if (still_not_crashed)
{
display_copyright_message();
do_nothing_loop();
basically_run_windows_3.1();
do_nothing_loop();
do_nothing_loop();
}
}

if (detect_cache())
disable_cache();

if (fast_cpu())
{
set_wait_states(lots);
set_mouse(speed, very_slow);
set_mouse(action, jumpy);
set_mouse(reaction, sometimes);
}

/* printf("Welcome to Windows 3.11"); */
/* printf("Welcome to Windows 95"); */
/* printf("Welcome to Windows 98"); */
/* printf("Welcome to Windows ME"); */
printf("Welcome to Windows XP");
if (system_ok())
crash(to_dos_prompt);
else
system_memory = open("a:\swp0001.swp" O_CREATE);

while(something)
{
sleep(5);
get_user_input();
sleep(5);
act_on_user_input();
sleep(5);
}
create_general_protection_fault();
}

I hope programmers here can help me.
Tnanks!

Bill Gates,
Microsoft Corp.
One Microsoft Way
Redmond, WA 98052-6399
Telephone: (425) 882-8080

Re: Please help me to fix a bug in Windows XP.

Michael Martin21-Jul-01 22:32

Michael Martin

21-Jul-01 22:32

This wasn't even funny the first time I saw it, and I was an OS/2 Warp 3 zealot at the time. Original or funny stuff only thanks.

Michael Martin
Pegasystems Pty Ltd
Australia
martm@pegasystems.com
+61 413-004-018

MFC icons

Stephen McGeown21-Jul-01 13:27

Stephen McGeown

21-Jul-01 13:27

Hi folks,

I hope one of you out there can help me with a small problem.

Does anyone know how to override the MFC default icons in my MFC app wizard application that Microsoft kindly provide? It's the small icon that appears at the top left corner of the main window that I want to replace in particular.

I even removed them from the resources and replaced them with my own icons, but to no avail. I had a look at the MSDN library help for PreCreateWindow and CREATESTRUCT but there's nothing obvious there.

Any suggestions would be great.

Cheers, Stephen.

Re: MFC icons

Michael Martin21-Jul-01 23:00

Michael Martin

21-Jul-01 23:00

Here is the answer

Michael Martin
Pegasystems Pty Ltd
Australia
martm@pegasystems.com
+61 413-004-018

Re: MFC icons

Stephen McGeown22-Jul-01 4:11

Stephen McGeown

22-Jul-01 4:11

Thanks Michael. That's me up an running now.

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