C / C++ / MFC

30-Jul-03 15:06

This is the default windows behavior. Unless it is absolutly necissary I would not change it because it will confuse your users who will expect to be able to edit the box.

John

Child dialogs in Win32

bluecombtiller30-Jul-03 7:06

bluecombtiller

30-Jul-03 7:06

Hey! I'm trying to get a child dialog to show up in a pure Win32 app.

What I want to do is use the dialog as half of the UI and use a simple ListBox (created with CreateWindowEx) as the other half.

Here's what I'm trying:
hCtrls = CreateDialog( hInst, (LPCTSTR)IDD_GAMEINFO, hWnd, (DLGPROC)DlgGameInfo );

The line of code works for all non-child dialogs (like my About and Options dialogs), however as soon as I specify in the resource editor that my IDD_GAMEINFO should be a child it doesn't work.

Any help is appreciated! Thanks
./[tiller]

l a u r e n30-Jul-03 7:21

l a u r e n

30-Jul-03 7:21

whats the hWnd ur passing?

"penguins have no bill"
biz stuff about me

bluecombtiller31-Jul-03 7:10

bluecombtiller

31-Jul-03 7:10

The hWnd is the HWND variable that the main window's WndProc message handler recieves.

In the switch statement for the various windows messages I basically have the following to create my UI:

case WM_CREATE:

HWND hCtrls;
// Listbox works
hCtrls = CreateWindowEx( WS_EX_CLIENTEDGE, "LISTBOX", "",
WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_HSCROLL,
5, 5, 200, 340, hWnd, (HMENU)IDC_GAMELISTBOX,
GetModuleHandle(NULL), NULL);

// Static frame works
hCtrls = CreateWindowEx( WS_EX_CLIENTEDGE, "STATIC", "",
WS_CHILD | ~WS_VISIBLE | SS_GRAYFRAME,
210, 5, 250, 340, hWnd, (HMENU)IDC_GAMEINFOFRAME,
GetModuleHandle(NULL), NULL);

// CreateDialog returns a NULL (IDD_GAMEINFO is my dialog resource)
hCtrls = CreateDialog( hInst, (LPCTSTR)IDD_GAMEINFO, hWnd,
(DLGPROC)DlgGameInfo );

// I also added this later to try it...but it didn't help:
ShowWindow( hCtrls, SW_SHOWNORMAL );
UpdateWindow( hCtrls );

I experimented a bit...the code with no modification works if I specify in the resource editor that the dialog is a regular popup with a border, etc. But of course then it's a popup...and I want it a part of the actually window. (Like a common control would be)
Thanks,
./[tiller]

andyj1151-Aug-03 4:30

andyj115

1-Aug-03 4:30

Not sure that this is your case, but for child dialogs you have to ensure that the WS_VISIBLE style attribute is set in the resource.

Cool | :cool:

Dynamic array initialization.

bluecombtiller1-Aug-03 9:13

bluecombtiller

1-Aug-03 9:13

Yeah...I have WS_VISIBLE selected.
./[tiller]

⁷³Zeppelin30-Jul-03 6:37

⁷³Zeppelin

30-Jul-03 6:37

I have a member variable of a class declared as a pointer to type double, m_dHessianMatrix. This variable will be holding a 2 x 2 matrix (could be larger)and needs to be initialized completely to zeroes to start. As such, I need something to init the matrix to zero quickly (thus a for loop will not do particularly for LARGE matrices).

Currently I am initializing the matrix data in the constructor as follows:

//////////////////////////////////////////////////////
// CROT_Optimizer()
//
// NOTES: Constructs a ROT_Optimizer object
//        to be used as the quasi-Newton 
//        nonlinear optimization engine
//
// ACCEPTS: The number of nodes in the springs
//			network to be optimized
//
// RETURNS:
//
CROT_Optimizer::CROT_Optimizer(UINT MaxNodes)
{
	ASSERT (MaxNodes > 0);

	if (MaxNodes == 0)
		return;

	m_uiNumberOfNodes = MaxNodes;	// we NEED the number of nodes
	m_uiNumberOfSprings = 0;

	// Pointer initializations
	m_ppNodeIndexedSpringArray = NULL;
	m_dHessianMatrix = NULL;

	m_dHessianMatrix = new double[4];  // a 2 x 2 matrix
	memset(m_dHessianMatrix, 0, sizeof(double));

}

However, I don't like this for two reasons.

1.) I have to include string.h to gain access to the memset function ->code bloat Dead | X|

2.) It is not aesthetically pleasing to the eye Cool | :cool:

Is there a way to initialize the matrix without using a for loop and without using memset()?

Re: Dynamic array initialization.

John M. Drescher30-Jul-03 6:39

Re: Dynamic array initialization.

30-Jul-03 6:39

I use ZeroMemory.

John

⁷³Zeppelin30-Jul-03 6:49

⁷³Zeppelin

30-Jul-03 6:49

Ah, ok. One question.

If I have a 4 element matrix, is the proper syntax:

ZeroMemory(&m_dHessianMatrix, sizeof(double));
<pre><code>
ZeroMemory(&m_dHessianMatrix, 4*sizeof(double));

?

(Thanks for the suggestion)

Re: Dynamic array initialization.

John M. Drescher30-Jul-03 6:54

MFC/ATL thread syncronization

30-Jul-03 6:54

ZeroMemory(&m_dHessianMatrix, 4*sizeof(double));

John

alma30-Jul-03 6:26

alma

30-Jul-03 6:26

What functions/classes should I use for thread syncronization inside a module that is used in both ATL and MFC projects?

-Alma-

Re: MFC/ATL thread syncronization

John M. Drescher30-Jul-03 6:37

Re: MFC/ATL thread syncronization

30-Jul-03 6:37

Use the win32 API. CreateEvent(), CreateMutex() ...

John

alma30-Jul-03 11:19

alma

30-Jul-03 11:19

Yeah, right!
Smile | :)

Thanks!
-Alma-

Abstract Class

Mahesh Varma30-Jul-03 5:43

Mahesh Varma

30-Jul-03 5:43

Hi all,

How can i create an abstract class without using virtual keyword in c++.

Mahesh

#realJSOP30-Jul-03 5:47

#realJSOP

30-Jul-03 5:47

You can't.

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Jonathan de Halleux30-Jul-03 5:49

Jonathan de Halleux

30-Jul-03 5:49

??? If you use inherance overloading without virtual you will run into trouble.

If you want to avoid virtual methods, use template meta programming.

Jonathan de Halleux.

ZoogieZork30-Jul-03 6:16

ZoogieZork

30-Jul-03 6:16

Is there a particular reason you don't want to use virtual? Confused | :confused:

- Mike

John M. Drescher30-Jul-03 6:54

30-Jul-03 6:54

I was thinking the same.

John

Mahesh Varma30-Jul-03 19:03

Mahesh Varma

30-Jul-03 19:03

Hi Mike,

Thanks.. No particular reason mike. It was an interview question.
I just want to confirm whether it is possible.

Mahesh

Navin30-Jul-03 6:31

Navin

30-Jul-03 6:31

You can't - an abstract class is defined as having at least one method be virtual and not having an implementation. e.g.,

class VirtualClass
{
public:
   virtual void OverrideMe() = 0;
};

A compiler won't let you instantiate such a class. If you can instantiate it, then it is not an abstract class.

"When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute and it's longer than any hour. That's relativity." - Albert Einstein