C / C++ / MFC

28-May-07 19:55

Hi,

I have got a very basic question. Do WS_POPUP style windows get created in a separate thread than the thread which created them or do they run in the same thread and somehow also manage a message loop?

Thanks,

---

Hakuna-Matada Beer | [beer]

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Naveen28-May-07 20:00

28-May-07 20:00

HakunaMatada wrote:
Do WS_POPUP style windows get created in a separate thread

no. When you call createwindow() from a thread, what ever be its style, it is created in same thread.

nave

HakunaMatada28-May-07 21:04

28-May-07 21:04

Thanks for taking the time out to reply but I do have some more queries.

Naveen R wrote:
no. When you call createwindow() from a thread, what ever be its style, it is created in same thread.

If so, then what about the message loop. If I have a MainFrame window which in turn is creating 5 Popup windows, I believe that every window will have its own message loop. How does it maintain 6 message loops within the same thread?

Thanks.

---

Hakuna-Matada Beer | [beer]

It means no worries for the rest of your days...
It's our problem free, Philosophy
Jig | [Dance]

Naveen28-May-07 21:15

28-May-07 21:15

HakunaMatada wrote:
I believe that every window will have its own message loop

No. Only one meesage loop will be there. When a window is created, there will no message loop. we have to explicitly write the message after creating the function( MFC is internally doing this). In the MainFrame case you said the sequence will be...

1. Create MainFrame
2. Create 5 popup window
3. Start the message loop

     while( GetMessage())// this loop is normally called as message loop<br />
{<br />
	TranslateMessage();<br />
	DispatchMessage();<br />
}

you can find this message loop in the CWinThread::PumpMessage() function.

nave

HakunaMatada28-May-07 21:42

28-May-07 21:42

So, what you are saying is that there is just one message loop which gets created and the framework makes it seem like all have separate message loops?

Lets say for example...

1) Create MainFrame.
2) Run Message Loop.
3) Create 5 Popup windows on an event, say button click.

Lets say the classes for the Mainframe and Popup windows are CMainFrame, CPopup1, CPopup2.... etc. All classes have their own message loops(BEGIN_MSG_MAP and END_MSG_MAP). Does the framework being used make us think that separate message loops are being used when in reality only message loop is being used or is the case otherwise?

Thanks again for the answers.

---

Hakuna-Matada Beer | [beer]

It means no worries for the rest of your days...
It's our problem free, Philosophy
Jig | [Dance]

Naveen28-May-07 21:53

28-May-07 21:53

HakunaMatada wrote:
All classes have their own message loops(BEGIN_MSG_MAP and END_MSG_MAP)

BEGIN_MSG_MAP and END_MSG_MAP are not message loop, they are message maps. The function added between that macro will be called by the MFC framework when a message of corresponing type arrives in that window.

The better method to explorer this type of thing is to step in to the code of MFC while debugging.

nave

HakunaMatada28-May-07 23:23

28-May-07 23:23

Thanks for the info.

---

Hakuna-Matada Beer | [beer]

It means no worries for the rest of your days...
It's our problem free, Philosophy
Jig | [Dance]

jhwurmbach28-May-07 22:34

jhwurmbach

28-May-07 22:34

HakunaMatada wrote:
o WS_POPUP style windows get created in a separate thread than the thread which created them or do they run in the same thread

Windows styles (like WS_POPUP) and threads are orthogonal concepts.
WS_POPUP is about adorning your window (and maybe raising expectations in the user of your window).
What you want to learn about is worker threads and UI threads!

Maybe this[^] helps?

Failure is not an option - it's built right in.

HakunaMatada28-May-07 23:36

28-May-07 23:36

Thanks.

---

Hakuna-Matada Beer | [beer]

It means no worries for the rest of your days...
It's our problem free, Philosophy
Jig | [Dance]

NtQueryInformationFile

nitin328-May-07 19:39

nitin3

28-May-07 19:39

hi
Is there any example to understand this api

thanks

Naveen28-May-07 19:48

28-May-07 19:48

check this article http://www.codeproject.com/system/Task_Manager_Extension.asp[^]

nave

nitin328-May-07 19:54

nitin3

28-May-07 19:54

thanks
is there any simple example

Naveen28-May-07 19:59

28-May-07 19:59

another one

http://www.codeguru.com/Cpp/W-P/system/processesmodules/article.php/c2827[^]

nave

creating submenu for a menu

Hamid_RT28-May-07 20:05

Hamid_RT

28-May-07 20:05

Or see Retrieving the parent of a process (WinNT) [^]

WhiteSky

prithaa28-May-07 19:28

prithaa

28-May-07 19:28

Hello,

I have created a menu like the following code

CMenu Data1;
Data1.CreateMenu();
Data1.AppendMenu(MF_STRING ,DataP, "Demand");

CMenu M;
M.CreateMenu();
M.AppendMenu(MF_POPUP ,(UINT)Data1.m_hMenu, "Data");
M.AppendMenu(MF_STRING, Model_EntityP,"Model Entity");
M.AppendMenu(MF_STRING ,EditP, "Edit");
pFrame->SetMenu(&M);

The above code works if I remove the popup Data1 option and then execute the program.
It doesn't allow me to create popups.
Where exactly popups should be added for me to see after I click on the topline menu?

Prithaa

nitin328-May-07 19:50

nitin3

28-May-07 19:50

CMenu Data1;
Data1.CreatePopupMenu();// try this code
Data1.AppendMenu(MF_STRING ,DataP, "Demand");

Naveen28-May-07 19:53

28-May-07 19:53

prithaa wrote:
M.AppendMenu(MF_POPUP ,(UINT)Data1.m_hMenu, "Data");

modify it as below

M.AppendMenu(MF_POPUP ,(UINT)Data1.Detach(), "Data");

nave

prithaa29-May-07 0:06

prithaa

29-May-07 0:06

Hello,

Thanks .
I did the required changes in the code and now I am getting the pull down menu which is grayed and not active.

How do I activate the pull down ?
I have written the following code for the pull down

M.AppendMenu(MF_STRING | MF_ENABLED ,DEMAND_ID, "DEMAND");
M.AppendMenu(MF_STRING | MF_ENABLED ,COST_ID, "COST");

Prithaa

Naveen29-May-07 0:31

29-May-07 0:31

Hi pritha..

overide the OnCmdMsg() function of the view class and return true when the

nID == DEMAND_ID or nId == COST_ID
and
nCode == CN_COMMAND

nave

prithaa29-May-07 1:34

prithaa

29-May-07 1:34

Hello,

What ever you have asked me to do it has worked for me .But I don't understand why I have done that.

Especially the OnCmdMsg().Why this method when I have set the nFlags as MF_ENABLED.

You can give me any reference on the topics if explaining the whole thing is tedious.

Thanks It works
Prithaa

Naveen29-May-07 14:57

29-May-07 14:57

prithaa wrote:
Why this method when

Actaully MFC didnt says to do so. In MSDN they are telling to add dummy command handler if we want a menu to be active.

from MSDN:
Disabling the Automatic Disabling of Button Controls
If you place a button control on a dialog bar, or in a dialog using where you are calling CWnd::UpdateDialogControls on your own, you will notice that buttons which do not have ON_COMMAND or ON_UPDATE_COMMAND_UI handlers will be automatically disabled for you by the framework. In some cases, you will not need to have a handler, but you will want the button to remain enabled. The easiest way to achieve this is to add a dummy command handler (easy to do with ClassWizard) and do nothing in it.

nave

Naveen29-May-07 14:58