position of code matters? - C / C++ / MFC Discussion Boards

Ed K30-Aug-02 9:26

30-Aug-02 9:26

I have a small logging utility that I use across several different applications. When I try to use it from withing an NT Service I can't get any logging. Any gotchas you've run across regarding using COM from an NT Service?

Thanks,

ed

Re: NTService creating COM object problem

Vagif Abilov30-Aug-02 10:12

Vagif Abilov

30-Aug-02 10:12

In general, there is nothing that prevents COM components from being used in NT services. There are some issues you should know:

1. NT services run in a special account that don't interact with user, so if your component tries to display a message box, you're out of luck. Moreover, if you happen to use some MFC classes that cause assertion, they will end up (at least in DEBUG mode) displaying message box that will stop the service (of course without displaying anything).

2. Be careful with use of MFC user interface classes (in other words, don't use them). You can use MFC collection, thread and string classes.

The easiest way to discover what's wrong is to debug your service (select its process in task list, right-click and choose "debug").

Hope this helps.

Vagif Abilov
MCP (Visual C++)
Oslo, Norway

If you're in a war, instead of throwing a hand grenade at the enemy, throw one of those small pumpkins. Maybe it'll make everyone think how stupid war is, and while they are thinking, you can throw a real grenade at them.
Jack Handey, Deep Thoughts

Re: NTService creating COM object problem

Ed K30-Aug-02 11:13

Ed K

30-Aug-02 11:13

I don't use any user interface. I have a separate control panel applet that handles that. Working on the debugging though...

Thanks,

ed

Re: NTService creating COM object problem

Le centriste30-Aug-02 10:20

Le centriste

30-Aug-02 10:20

That may sound silly, but did you call CoInitialize?

Also, if you want to see pop-ups from your NT service, you choose "Interact with desktop" check box for the "LogON" tab in the service properties. That way, you may see any assertion failed dialog boxes.

Michel

It is a lovely language, but it takes a very long time to say anything in it, because we do not say anything in it, unless it is worth taking a very long time to say, and to listen to.

- TreeBeard

Re: NTService creating COM object problem

Ed K30-Aug-02 11:08

Ed K

30-Aug-02 11:08

I did. I use a little struct (below - found somewhere??) to initialize and uninitialize.

<br />
struct CComInit {<br />
	CComInit() { CoInitialize(NULL);  }<br />
	~CComInit() { CoUninitialize(); }<br />
};<br />

Then during initialization:

<br />
CComInit comInit;<br />

Thanks...

ed

Re: NTService creating COM object problem

Jörgen Sigvardsson30-Aug-02 11:52

Jörgen Sigvardsson

30-Aug-02 11:52

If you're compiling an ATL com server, be sure to see if you've got ATL_MINCRT defined. (I think that's the right name..)

IIRC, global object constructors are not called if you use this optimization since the libc is not there to do it for you...

Preferred storyline:
- I am your father. Search your feelings and you'll know it's the truth. Together we can rule this galaxy like father and son.
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Re: NTService creating COM object problem

Anders Molin30-Aug-02 12:32

Anders Molin

30-Aug-02 12:32

I have used a lot of COM from services, and have never had a single problem with it.

Just remember that if you write your log to a shared directory on another computer, the default account a service is running under (Local System) don't have access to network resources...

What happens?
Do you create the COM object successfully?

If you have written the COM object yourself, you might use some TRACE in the object so you can see what happens...

- Anders

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

position of code matters?

ns30-Aug-02 9:23

30-Aug-02 9:23

I had in my OnInitialUpdate this fragment at the end of the function:

 if(NULL != m_THBImage1.GetSafeHwnd())

{
    m_THBImage1.MoveWindow(10,10,200,180);
    m_THBImage2.MoveWindow(10,200,200,180);
    m_THBImage3.MoveWindow(10,390,200,180);
    m_THBImage4.MoveWindow(10,580,200,180);

}

Well, the code would run and never go into the block, so that my controls were higgledy piggledy on the screen. I moved it to the start of the function, and it works (though one time it crashed and didnt move the imageboxes). I am uneasy about why the crash and why the relocation works.

Most of the code in the OnInitialUpdate function does database access and sets things up.

The same relocation trick worked for the following in the same function:

if(NULL != m_listdisplay.GetSafeHwnd())

{
m_listdisplay.SetExtendedStyle(LVS_EX_CHECKBOXES);
m_listdisplay.InsertColumn(0,"Options",LVCFMT_LEFT,800);
}

If it was at the end of the function, my listctrl would come up blank with no columnheader, and when moved up, its okay.

The one time it crashed (even after moving the code up), the list ctrl was blank and there was no columnheader. I cant reproduce it but am extremely nervous.

Appreciate your insight.
Thanks,
ns Confused | :confused:

Re: position of code matters?

Ravi Bhavnani30-Aug-02 12:32

Ravi Bhavnani

30-Aug-02 12:32

Seems like you're returning before it can get to the code. A TRACE statement could verify this.

ns wrote:
higgledy piggledy
I have to add this term to my glossary. Smile | :)

/ravi

Let's put "civil" back in "civilization"
http://www.ravib.com
ravib@ravib.com

CHeaderCtrl messages from CListView based View

JennyP30-Aug-02 7:34

JennyP

30-Aug-02 7:34

Hello,

I've read the article here about getting header control messages from a CListCtrl. It describes how CHeaderCtrl is in CListCtrl and how to reassign (from the wizard) the dialog item ID to 0 for CHeaderCtrl in rerouting messages. However, my case is slightly different. My main view is derived directly from CListView:

class CMyMainView : public CListView

... and in this case, the wizard places ON_NOTIFY_REFLECT macros for all messages. I would like this class to handle some header events (such as click on header button to sort) but I cannot seem to find a way to route the message to where I want.

Any help/pointers to resources?

Thanks!

JennyP

Re: CHeaderCtrl messages from CListView based View

Tomasz Sowinski30-Aug-02 7:52

Tomasz Sowinski

30-Aug-02 7:52

Can you use LVN_COLUMNCLICK?

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

Pointer to Document

Kash30-Aug-02 7:01

Kash

30-Aug-02 7:01

I have embedded a Property sheet inside CFormView and I want to access the data inside my Document class.

I tried the following command in the first page of my property sheet:

m_doc=(CMyDoc*)GetTopLevelFrame()->GetActiveDocument();
ASSERT_VALID(m_doc);
data=m_doc->GetData();

but keep getting debug assertion error.
I think it's due to my application being MDI as a pose to SDI as the above code works for the latter.

Any suggestions on the command for MDI?

Cheers
Kash

Re: Pointer to Document

JennyP30-Aug-02 7:27

JennyP

30-Aug-02 7:27

Here's the boiler-plate code I use for this:

CDoc* pDoc = (CDoc*)((CMainFrame *)<br />
    AfxGetApp()->m_pMainWnd)->GetActiveFrame()->GetActiveDocument();

JennyP

Re: Pointer to Document

Kash30-Aug-02 8:29

Kash

30-Aug-02 8:29

Thank You very much

It works a treat.

gaining back lost focus

Anonymous30-Aug-02 6:38

Anonymous

30-Aug-02 6:38

Hi,

I have a text editor (CHtmlEditView) with a current font selection combobox on the toolbar so that the user can change the font type.
However when the cursor is placed on a row with different font than the current selection in the combobox, the combobox must be programmatically updated.
All this works fine except that the focus stays with the updated combo. In this case a second click is necessery to get back the cursor to the desired position ( after the first click the focus goes to the combo) and this might be annoying to the user.

I tried calling SetFocus on the mainframe but this does not place the cursor back to its previous position.

Please help!

R.

Adding spin control to ListCtrl

dennisV30-Aug-02 6:10

dennisV

30-Aug-02 6:10

Hello, was anyone successful in adding a spin control to a ListCtrl? I only see people adding drop-down boxes or the standard edit controls, but I need a spin control (or a scroll bar, whatever). Confused | :confused:

I'd appreciate any help on this.
Thank you in advance,

Dennis

MCP, MCSD

zooming problem

Zayax30-Aug-02 5:29

Zayax

30-Aug-02 5:29

Hi I'm trying to draw a line and two small circle at both end of that line. When I zoom in, I want only the lenght of the line to be extended and the circle size to be the same. But what happen was the circle size also increase. Anyone know how to fix that circle size even when zooming?
Thanks.

Newbies

Re: zooming problem

C^hris L^osinger30-Aug-02 5:46

C^hris L^osinger

30-Aug-02 5:46

make the circle size inversely proportional to your zoom level

-c

For men use, if they have an evil turn, to write it in marble:
and whoso doth us a good turn we write it in dust.
-- Sir Thomas More

image effects!

Re: zooming problem

Zayax30-Aug-02 6:23

Zayax

30-Aug-02 6:23

Thanks! very good solution. Smile | :)

Newbies

Load Icons from DLL

Matt Newman30-Aug-02 5:02

Matt Newman

30-Aug-02 5:02

I want to add icons to a CImageList from a precompiled DLL, such as shell32.dll or a dll I compiled myself. I will know the index of the icon. Anyone know how I can do this? I don't want to have to compile the icons into the app so I can easliy update the icons.

- Suspicious | :suss:

Matt Newman / Windows XP Activist Suspicious | :suss:

-Sonork ID: 100.11179

"You can't seriously believe that you could get away with suing someone over quoting text from a message posted in a public forum, can you?" - John Simmons

Re: Load Icons from DLL

Tomasz Sowinski30-Aug-02 5:08

Tomasz Sowinski

30-Aug-02 5:08

Try with ExtractIconEx or LoadLibraryEx with LOAD_LIBRARY_AS_DATAFILE flag.

Tomasz Sowinski -- http://www.shooltz.com

Free your mind and your ass will follow.

Re: Load Icons from DLL

Matt Newman31-Aug-02 1:56

Matt Newman

31-Aug-02 1:56

Thanks, ExtractIconEx worked perfectly

- Suspicious | :suss:

Matt Newman / Windows XP Activist Suspicious | :suss:

-Sonork ID: 100.11179

"You can't seriously believe that you could get away with suing someone over quoting text from a message posted in a public forum, can you?" - John Simmons

Re: Load Icons from DLL

Brian Delahunty30-Aug-02 5:27

Brian Delahunty

30-Aug-02 5:27

I'd use ExtractIconEx Smile | :)

Regards,
Brian Dela Smile | :)

Re: Load Icons from DLL

Matt Newman31-Aug-02 1:57

Matt Newman

31-Aug-02 1:57

Thanks for the advice.

- Suspicious | :suss:

Matt Newman / Windows XP Activist Suspicious | :suss:

-Sonork ID: 100.11179

"You can't seriously believe that you could get away with suing someone over quoting text from a message posted in a public forum, can you?" - John Simmons

Re: Load Icons from DLL

Brian Delahunty1-Sep-02 0:41

Brian Delahunty

1-Sep-02 0:41

Matt Newman wrote:
Thanks for the advice.

No hassel

Regards,
Brian Dela Smile | :)

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