C / C++ / MFC Discussion Boards

Child wizard that don't allow to access the controls of his parent dialog (How to avoid?)

Joan M20-Jan-01 3:24

20-Jan-01 3:24

I have created a Wizard inside a dialog WS_CHILD | WS_VISIBLE | WS_TABSTOP,
and what I've found is that I cant access the other controls placed inside the dialog and outside the wizard.

Could you tell me how to avoid this?

Thank you in advance.

Re: Child wizard that don't allow to access the controls of his parent dialog (How to avoid?)

AlexMarbus21-Jan-01 12:19

AlexMarbus

21-Jan-01 12:19

Actually, in the parent dialog you should know as little as possible from the child dialogs. In the same way, in the child dialogs, you should know as little as possible from your parent dialog, except the fact that it is a CWnd-derived class.

When you need to have access on the controls on the parent-dialog, you are not developing object-oriented.. which is your own choice ofcourse Wink | ;)

Maybe a better (read: more OO) way is to define a custom message (Let's say WM_DO_SUMPIN), send a message to your parent, and let him(/her?) do whatever is necessary.

#define WM_DO_SUMPIN WM_USER + 15 // Just some value

GetParent()->SendMessage(WM_DO_SUMPIN, wParam, lParam);

(In the parent's class: )
ON_MESSAGE(WM_DO_SUMPIN, SomeFunction);

void CParentClass::SomeFunction(WPARAM wParam, LPARAM lParam)
{
// We should do sumpin' here..
}

.. or do some good thinking why you actually want to do something with that control.

--
Alex Marbus

How to get the "name -> WM_xxx" of a message if I have the numeric ID?

Joan M20-Jan-01 0:58

Joan M

20-Jan-01 0:58

I have used the Spy++ and get a numerical id (the 78) and I want to know wich message is it, could you explain me how to do it?

Thank you very much.

Re: How to get the

NormDroid20-Jan-01 1:45

NormDroid

20-Jan-01 1:45

Look in the Windows.h file,

78 = 0x004E which happens to be WM_NOTIFY.

Re: How to get the

Joan M20-Jan-01 1:54

Joan M

20-Jan-01 1:54

I'm a novice, but I've taken a look at this file and I can't see nothing related to WM_NOTIFY, could you give me more info please?

thank you in advance.

Re: How to get the

20-Jan-01 1:55

Sorry I misinformed you WINUSER.H, my apologies.

Norm

Re: How to get the

Joan M20-Jan-01 2:08

Joan M

20-Jan-01 2:08

Thank you very much! you has helped me a lot, this is very important in order to be more productive...

Re: How to get the

AlexMarbus21-Jan-01 12:26

AlexMarbus

21-Jan-01 12:26

If you don't know exactly where to look, you could also type the name in the VC editor, in this case WM_NOTIFY, rightclick on it, and select "Go to definition of..".
You'll see where it's defined, and the actual value of it.

--
Alex Marbus

Re: How to get the

Michael Dunn20-Jan-01 5:30

Michael Dunn

20-Jan-01 5:30

You can also look it up in VC if you're debugging. In the Watch window, enter "78,wm" (or whatever number) and VC will display the corresponding WM_* symbol.

--Mike--
http://home.inreach.com/mdunn/
Is history an illusion caused by the passage of time, or is time an illusion caused by the passage of history?

Network game

20-Jan-01 0:54

I am working on a game, and I want it to have network play capabilities,
LAN preferrably and without the MFC. It's a very small game, so it shouldn't be to advanced to implement. Does anybody have any idea how I can do this? I have never done a network game before.

Thanks in advance. Smile | :)

Erik

Re: Network game

NormDroid20-Jan-01 1:39

NormDroid

20-Jan-01 1:39

Good book to start with is the "Winsock 2.0 Programming" by Lewis Napper - Highly Recommended.
If there are more than 2 players, I would recommend client-server. Where the clients connect to a running server app. You could use Winsock API direct or use the MFC wrapper classes (CAsyncSocket & CSocket).

Another strategy would to use DCOM and connection points, here you could start with Professional ATL Programming by Richard Grimes - Good book.

If could be even possible with SOAP, I don't have even knowledge to advise you on this one.

Look around on this site in the Internet Section also look in www.codeguru.com.

Good Luck

Opening the CD ROM drive

Ashman20-Jan-01 0:47

Ashman

20-Jan-01 0:47

Hi all,
I am writing an MFC app for my friend who finds it hard to open the CD ROM drive by pressing the buttons on the CD-DRIVE.
He has 3 drives, and I want individual ones to open by pressing the button Open.

Can I do this?
How?
Thanks
Ashman
PS: Please be detailed, Im rather dumb =)

Re: Opening the CD ROM drive

24-Jan-01 2:56

You need to use the media control interface (MCI).
You can send strings or commands to the MCI to get things done.

Set CDAudio Door Open
Set CDAudio Door Close

I don't know how to address more than one CD this way.
Its different using the command API rather than the string API.

see also Microsoft knowledge base article: Q109371

Stephen

Small question about MFC\DIALOG

Ahmad19-Jan-01 21:01

Ahmad

19-Jan-01 21:01

-Enter and ESC keys close the dialog how i can stop it .
-How i can load accelerator from resource to MFC\DIALOG
i use loadaccelerator function but it didn't work.
thank you ...

Re: Small question about MFC\DIALOG

19-Jan-01 21:37

The best way is to try a keyboard Hook. That we you are totally in control of what's hapenning.

Re: Small question about MFC\DIALOG

Christian Graus19-Jan-01 23:09

Christian Graus

19-Jan-01 23:09

You stop it by overriding OnOK and OnCancel. You can make the buttons still work by checking the keystate with GetKeyState(VK_RETURN) (or VK_ESCAPE) and returning if they are down. Then your button works, but the key does not.

Christian

The content of this post is not necessarily the opinion of my yadda yadda yadda.

To understand recursion, we must first understand recursion.

Duplicate entries inside my std::map. Why?

Alvaro Mendez19-Jan-01 10:48

Alvaro Mendez

19-Jan-01 10:48

Hi,

I have structure that looks similar to this:

struct MyInfo
{
  CString m_str1;
  CString m_str2;
  COleDateTime m_dtm1;
  CString m_str3;
 
  MyInfo(const CString& str1, const CString& str2, const COleDateTime& dtm1, const CString& str3) : 
    m_str1(str1), m_str2(str2), m_dtm1(dtm1), m_str3(str3)
  { }
 
  bool operator<(const MyInfo& info)
  {
    return (m_str1 < info.m_str1 ||
            m_str2 < info.m_str2 ||
            m_dtm1 < info.m_dtm1 ||
            m_str3 < info.m_str3);
  }
};

I have a map of MyInfo to CString values, like this:

std::map< MyInfo, CString > mapInfo;

I insert/update elements into the map using operator[], like this:

void accumulate(const CString& str1, const CString& str2, const COleDateTime& dtm1, const CString& str3, const CString& strValue)
{ 
  mapInfo[MyInfo(str1, str2, dtm1, str3)] += strValue;
}

Notice that strValue is appended to whatever is already there.

Then later I iterate through every element in the map, but the problem is that I'm getting duplicate entries in the map (for the same MyInfo object). Why?

Thanks,
Alvaro

Re: Duplicate entries inside my std::map. Why?

C^hris L^osinger19-Jan-01 11:35

C^hris L^osinger

19-Jan-01 11:35

...i just tried your code (with slight modifcations to make it compile) and it worked fine, no duplicate entries.

i even did two identical "accumulate" calls in a row, to try to duplicate keys. when i dumped the map, though, the keys were unique.

-c

Re: Duplicate entries inside my std::map. Why?

Alvaro Mendez22-Jan-01 5:54

Alvaro Mendez

22-Jan-01 5:54

I really appreciate you looking into this problem for me Chris! Unfortunately I wasn't expecting to receive a "could not reproduce it" response otherwise I would have taken greater care to avoid it.

Here's how I was able to reproduce this problem. I took my sample code into a new MFC dialog based application I called "Doodle". I added a button to it and then a handler which I called OnButtonTryMap. Then inside I called the (global) accumulate function 100 times to insert/update the same MyInfo objects to the map each time. Here's how it looked:

#pragma warning (disable:4786)  // disables: identifier was truncated to '255' characters in the debug information
#include <map>

struct MyInfo
{  
	CString m_str1;  
	CString m_str2;  
	COleDateTime m_dtm1;  
	CString m_str3;   
	
	MyInfo(const CString& str1, const CString& str2, const COleDateTime& dtm1, const CString& str3) :     
		m_str1(str1), m_str2(str2), m_dtm1(dtm1), m_str3(str3)  
	{ }   
		
	bool operator<(const MyInfo& info) const  
	{    
		return (m_str1 < info.m_str1 ||            
				m_str2 < info.m_str2 ||            
				m_dtm1 < info.m_dtm1 ||            
				m_str3 < info.m_str3);  
	}
};
 
// Global objects (for testing purposes of course)
std::map< MyInfo, CString > g_mapInfo;
const COleDateTime g_dtmCurrent = COleDateTime::GetCurrentTime();
 
void accumulate(const CString& str1, const CString& str2, const COleDateTime& dtm1, const CString& str3, const CString& strValue)
{   
	g_mapInfo[MyInfo(str1, str2, dtm1, str3)] += strValue;
}
 
void CDoodleDlg::OnButtonTryMap() 
{
	CString str1, str2, str3;
	COleDateTime dtm = g_dtmCurrent;
 
	// Add the same 100 items each time this handler is called
	for (int iItem = 0; iItem < 100; iItem++)
	{
		str1.Format("str1 = %d", iItem);
		str2.Format("str2 = %d", iItem + 1);
		str3.Format("str3 = %d", iItem + 2);
		dtm += 1;

		accumulate(str1, str2, dtm, str3, str1);
	}
 
	// This should be 100 but...
	CString strMessage;
	strMessage.Format("There are %d items in the map.", g_mapInfo.size());
	AfxMessageBox(strMessage);
}

Try this and see if you get the same results. The first time I press the button I get "100 items" in the message. The second time, I get 118! The third time I get 142, then 154, and so on. If I've done this correctly, I should always see 100 items, shouldn't I? Confused | :confused:

Thanks for your help,
Alvaro

Re: Duplicate entries inside my std::map. Why?

Alvaro Mendez22-Jan-01 8:16

Alvaro Mendez

22-Jan-01 8:16

You hit the nail on the head! It's the ambiguous comparison that's causing the problem. How could I have been so blind? I changed the less-than operator to this and now it works as expected:

bool operator<(const MyInfo& info) const  
{    
	return ((m_str1 < info.m_str1) ||
		(m_str1 == info.m_str1 && m_str2 < info.m_str2) ||
		(m_str1 == info.m_str1 && m_str2 == info.m_str2 && m_dtm1 < info.m_dtm1) ||
		(m_str1 == info.m_str1 && m_str2 == info.m_str2 && m_dtm1 == info.m_dtm1 && m_str3 < info.m_str3));
}

Thanks for your help!
Alvaro

Re: Duplicate entries inside my std::map. Why?

C^hris L^osinger22-Jan-01 7:58

C^hris L^osinger

22-Jan-01 7:58

the problem is in your operator < function.

if MyInfo a = {"E", "A", xxx, xxx} MyInfo b = {"A", "E", xxx, xxx}

a will always be less than b; and b will always be less than a. but std::map requires that the comparison is strict. a < b or b < a, not both.

there's a good chance the ambiguous comparison is screwing with the map's tree.

-c

Re: Duplicate entries inside my std::map. Why?

Alvaro Mendez22-Jan-01 7:10

Alvaro Mendez

22-Jan-01 7:10

Chris,

In this example you're right because str1 is different for every element in the map. But what if str1 where not always different? If str1 were sometimes the same value as in previous elements then the solution you propose would not work. In other words, if in the for loop you put:

str1 = "a";

instead of

str1.Format("str1 = %d", iItem);

then we would still have 100 unique items but your solution would yield only 1. So the problem does not appear to be in the less-than operator. It's something else which too me smells like a bug in the std::map code.

Anyone have a clue?

Thanks,
Alvaro

Open up a dialog resource from a DLL

kk919-Jan-01 10:34

kk9

19-Jan-01 10:34

Hi
Does anyone know how to open up a dialog resource from a DLL? I am using LoadLibrary to load DllA.dll which contains IDD_DIALOGA resource. Then find the resource handle by using FindResource and LoadResource functions. However, I don't know what to do with the return value from LoadResource. Does anyone know if there is a way to open up IDD_DIALOGA resource from that handle in the client application?

VERIFY(hModule = ::LoadLibrary("DllA.dll"));
HRSRC hDialogA = ::FindResource(hModule, "#7000", RT_DIALOG);
LPVOID lpvResource = (LPVOID) ::LoadResource(hModule, hDialogA);

Thanks alot for your time!

kk9

Re: Open up a dialog resource from a DLL

David Fedolfi19-Jan-01 10:48

David Fedolfi

19-Jan-01 10:48

I use the following:

HINSTANCE h = (HINSTANCE)::GetModuleHandle(pszDllName);
ASSERT(h);
HINSTANCE hPrevious = AfxGetResourceHandle();
AfxSetResourceHandle(h);

// Do your Processing here

if(hPrevious)
AfxSetResourceHandle(hPrevious);

Activate window in Win2000

Mike Melnikov19-Jan-01 3:36

Mike Melnikov

19-Jan-01 3:36

I want to maximise window from SystemTray.

after calling DrawAnimatedRects for my window

I tried to use SetActiveWindow();
SetForegroundWindow();
and even ModifyStyleEx(0,WS_EX_TOPMOST)

and it works in WinNT but not Win2000
can anybody help me?

Mike. Confused | :confused:

Last Visit: 31-Dec-99 18:00 Last Update: 20-Jun-24 4:48

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