C / C++ / MFC Discussion Boards

ChiYung26-Mar-02 6:34

26-Mar-02 6:34

Hi,

Do I need to use criticalSEction to both READ and WRITE operation to an share array (by several thread)

Tim Smith wrote:
Yes, because if you don't then you run the risk of reading while someone is writing and thus the data might be suspect.

I need to use CCriticalSection in both READ and WRITE the share array by several threads.....right?

So, what i need to do is:

1. Declare a global CCriticalSection variable (e.g. CCriticalSection cs; )
2. Use cs.Lock() and cs.Unlock() to lock all section that involve READ and WRITE (no matter these operation is in NORMAL function or THREAD function....right?)

That's it??? Please correct me if I am wrong.

Re: (repost) CriticalSection Question

Le centriste26-Mar-02 6:35

Le centriste

26-Mar-02 6:35

yes, that's it. Try to avoid deadlocks though. I mean, make sure that all exit path pass through an cs.Unlock().

Michel

If I am wrong or said something stupid, I apologize in advance Wink | ;)

Re: (repost) CriticalSection Question

Tomasz Sowinski26-Mar-02 11:35

Tomasz Sowinski

26-Mar-02 11:35

Don't play with cs.Lock/cs.Unlock - it's not exception safe. Use CSingleLock instead - it takes care of locking.

Tomasz Sowinski -- http://www.shooltz.com
** If you're going to rape, pillage and burn, be sure to do things in that order. **

Edit Boxes

26-Mar-02 6:33

I am desinging an application with a dialog box.

Can someone tell me how to load the string inside of a edit box to a combo box. Then after i update the data, how do i make it so that only while the application is running, it stores the current information in the combo box and after every time i change the value of the edit box string and press a button to add it to the combo box.;P

Re: Edit Boxes

Mazdak26-Mar-02 8:03

Mazdak

26-Mar-02 8:03

editbox.GetWindowText(str);
combobax.Add(str);

Mazy

"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975

Bitmaps

26-Mar-02 5:52

I have a bitmap resource in my application. Can somebody please wither explain to me how to make the bitmap disappear when clicking on a button or, give me sample code to do this.

Greatly Appreciated. Smile | :)

Bitmaps Disappearing

26-Mar-02 4:47

Can someone please explain to me how i can get a bitmap inside of my application to disappear with the push of a button?
Thanks! Big Grin | :-D

Re: Bitmaps Disappearing

dazinith26-Mar-02 5:53

dazinith

26-Mar-02 5:53

where is the bitmap? is it a CStatic control you've put in a dialog, or what? details?

-dz

Re: Bitmaps Disappearing

26-Mar-02 6:02

I have it in a dialog window, it is a CStatic control. I have made a function that sorts through a small database of people and i also want their picture to show up that i have loaded in the resources. I dont know how to do that and im searching frantically to do so. So if i figure out how to do that, then i'll probably figure out how to make them disappear.

Re: Bitmaps Disappearing

Joaquín M López Muñoz26-Mar-02 6:54

Joaquín M López Muñoz

26-Mar-02 6:54

Try with m_yourBitmap.SetBitmap(IDB_BITMAP) to set the bitmap IDB_BITMAP as stored in your resources, and m_yourBitmap.SetBitmap(NULL) to clear it up. Remeber your CStatic has to have the SS_BITMAP style.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

entry-point and UNICODE

Jean-Michel LE FOL26-Mar-02 4:28

Jean-Michel LE FOL

26-Mar-02 4:28

I don't remember what entry-point I must specified in an MFC project file when I compile in UNICODE. Could you help me ? Thanks.

Re: entry-point and UNICODE

Tim Deveaux26-Mar-02 4:50

Tim Deveaux

26-Mar-02 4:50

wWinMainCRTStartup

WM_LBUTTONDOWN

NC26-Mar-02 3:26

26-Mar-02 3:26

Hi!
I want to get the message when the left mouse button is down on a tree ctrl. But this tree ctrl is of type CTreeCtrl and not of any class derived from CTreeCtrl. So, when I add a handler for this message in the dialog that holds this tree ctrl, it doesn't recieve this message! It recives only when the left mouse is down on the dlg and not when it is down on the tree ctrl. How can I get this message when the left mouse button is down on the tree ctrl.

Thanks,

NC

Re: WM_LBUTTONDOWN

26-Mar-02 3:42

what do you mean by
" But this tree ctrl is of type CTreeCtrl and not of any class derived from CTreeCtrl. "

anyway,add the handler when the id of the tree is selected in the id list of the class wizard.you might have added for the dialog itself.

bye.

Re: WM_LBUTTONDOWN

NC26-Mar-02 4:13

26-Mar-02 4:13

Hi!
Thanks for replying.

There is not WM_LBUTTONDOWN for the tree ctrl. How else can I add this to message map and also add a handler?

Thanks,

NC

Re: WM_LBUTTONDOWN

Carlos Antollini26-Mar-02 3:45

Carlos Antollini

26-Mar-02 3:45

You need to Know if the pointer is in the TreeCtrol....
Get the mouse Pointer Position and ask if into the Square that define the control

Carlos Antollini.
Sonork ID 100.10529 cantollini

Re: WM_LBUTTONDOWN

NC26-Mar-02 4:14

26-Mar-02 4:14

Hi!
Thanks for answering.

Where do I check if the mouse position is on the tree ctrl?

Thanks,

NC

Re: WM_LBUTTONDOWN

Carlos Antollini26-Mar-02 9:03

Carlos Antollini

26-Mar-02 9:03

You can use CRect::PtInRect where the point is the mouse pointer and the Rect the TreeControl coordinates. Don't forguet to call CRect::NormalizeRect Before to call PtInRect Wink | ;)

Carlos Antollini.
Sonork ID 100.10529 cantollini

Re: WM_LBUTTONDOWN

Carlos Antollini26-Mar-02 9:03

Carlos Antollini

26-Mar-02 9:03

You can use CRect::PtInRect where the point is the mouse pointer and the Rect the TreeControl coordinates. Don't forguet to call CRect::NormalizeRect Before to call PtInRect Wink | ;)

Regards

Carlos Antollini.
Sonork ID 100.10529 cantollini

Re: WM_LBUTTONDOWN

Roger Allen26-Mar-02 6:24

Roger Allen

26-Mar-02 6:24

As you want to handle the WM_LBUTTONDOWN before it goes to the TreeCtrl, I would override PreTranslateMessage() as follows:

BOOL CYourDialog::PreTranslateMessage(MSG* pMsg) 
{
	if (pMsg->message == WM_LBUTTONDOWN)
		{
		// determine whether the mouse is on the tree ctrl
		CPoint p ;
		GetCursorPos(&p) ;
		CWnd *pWnd = GetWindowFromPoint(p) ;
		if (pWnd != NULL)
			{
			// its on a window, is it the correct window
			if (pWnd->GetDlgCtrlID() == ID_OF_TREE_CTRL && pWnd->GetParent() == this)
				{
				// its our tree control
				// put your code here
				}
			}
		}
	return CDialog::PreTranslateMessage(pMsg);
}

Its all written from memory, so some calls/parameters etc may not be correct, but it should do something close to what you need.

Roger Allen
Sonork 100.10016

If I'm not breathing, I'm either dead or holding my breath.
A fool jabbers, while a wise man listens. But is he so wise to listen to the fool?

GetActiveIndex() from a PropertySheet

26-Mar-02 3:25

Hi, I am trying to use GetActiveIndex() in the property sheet to get the index of an active page. I encountered a problem in GetTabControl() which returns 0xcccccccc. I believe the setup of my property sheet and pages should be right by using DoModal() and AddPage(). Please give me some suggestions on troubleshooting this problem. Thanks!

Re: GetActiveIndex() from a PropertySheet

Tomasz Sowinski26-Mar-02 3:32

Tomasz Sowinski

26-Mar-02 3:32

Are you calling GetTabControl before DoModal?

Tomasz Sowinski -- http://www.shooltz.com
** If you're going to rape, pillage and burn, be sure to do things in that order. **

Re: GetActiveIndex() from a PropertySheet

26-Mar-02 3:49

I called GetActiveIndex() after DoModal() and Addpages(). If I go straight to display data on the first page, it works fine when I am on the first page and vice versa on the other pages. However, I would like to display data by the active page which gives me more flexability.

Save Dialog Box

Anthony988726-Mar-02 3:21

Anthony9887

26-Mar-02 3:21

Hi, I'm trying to create a save dialog box with 2 filters. How can i update the extention in the filename whenever the "Save As Type" box is highlighted.

Thanks

debugging

Rajveer26-Mar-02 3:06

Rajveer

26-Mar-02 3:06

I've just started learning how to debug, and I'm still kinda new with C++ programming language.
I have two variables declared as doubles: x, slope
while debugging, I noticed that sometimes in the loop they're values came up as:
slope = 1.#INF000000000
x = -1.#IND000000000
what does that mean?....why does it happen?

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.