COM Discussion Boards

Tony Tullemans24-Jan-13 13:17

24-Jan-13 13:17

Greetings!

I have a complex scheduling application written in VB.NET (.NET Framework 4.0) that must use a Data Access Layer consisting of a bunch of C++ DLLs which are in-turn accessed via a COM API library. Of course when the COM API is referenced in the VB.NET application an Interop Assembly is created by Visual Studio.

The problem I am having is that some users are experiencing an APPCRASH (c0000005 exception code) several times per day, but this only occurs if they have the my application open all of the time and they are continually moving between it and other apps (e.g. to MS Word or MS Outlook etc). The APPCRASH occurs as soon as the shift their focus back to my application. I do have a suspicion as to why this may be occurring but my lack of knowledge of the way in which Windows and the .NET Framework manage memory precludes me from being sure.

My suspicion is that when users are using other applications for some time, and Windows requires more memory for those other apps, that it caches my app’s memory to disk. When they return to my app then Windows loads it back into memory, but because I am using COM it is placing the COM related memory into a different address and then when my app attempts to access the COM objects then an Access Violation is occurring and hence the APPCRASH. The faulting module is nearly always the COM API library, but sometimes it is ntdll.dll or clr.dll.

Does this sound like a reasonable hypothesis? And if so, what are my options (if any) for resolving this?

Here are a sample of problem signature traces. Note that they do not all have the same faulting module.

Signature du problème :
Nom d’événement de problème: APPCRASH
Application Name: VM2305.EXE
Application Version: 2.1.0.5
Application Timestamp: 4f44820b
Fault Module Name: a4wcomex.dll
Fault Module Version: 6.0.0.0
Fault Module Timestamp: 4cfb1354
Exception Code: c0000005
Exception Offset: 0001de92
Version du système: 6.0.6002.2.2.0.768.3
Identificateur de paramètres régionaux: 3084

Problem signature:
Problem Event Name: APPCRASH
Application Name: VM2305.EXE
Application Version: 2.1.0.9
Application Timestamp: 4fa218fd
Fault Module Name: clr.dll
Fault Module Version: 4.0.30319.261
Fault Module Timestamp: 4ec9f6ff
Exception Code: c0000005
Exception Offset: 00020ed1
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 4105
Additional Information 1: 93e2
Additional Information 2: 93e2ab0171a7a6ff1415f9bd2ed3bdf7
Additional Information 3: be03
Additional Information 4: be03af409f1ea363e69fa074d659b668

Problem signature:
Problem Event Name: APPCRASH
Application Name: VM2305.EXE
Application Version: 2.1.0.10
Application Timestamp: 4faca846
Fault Module Name: StackHash_0a9e
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 00000000
Exception Code: c0000005
Exception Offset: 08000400
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 3084
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

Problem signature:
Problem Event Name: APPCRASH
Application Name: VM2305.EXE
Application Version: 2.1.0.10
Application Timestamp: 4faca846
Fault Module Name: StackHash_0a9e
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 00000000
Exception Code: c0000005
Exception Offset: 41080414
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 3084
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

Problem signature:
Problem Event Name: APPCRASH
Application Name: VM2305.EXE
Application Version: 2.1.0.16
Application Timestamp: 4fea898a
Fault Module Name: a4wcomex.dll
Fault Module Version: 6.0.0.0
Fault Module Timestamp: 4cfb1354
Exception Code: c0000005
Exception Offset: 0001de92
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 4105
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

Re: AppCrash Issue related to COM?

Richard MacCutchan24-Jan-13 23:01

Richard MacCutchan

24-Jan-13 23:01

Tony Tullemans wrote:
Does this sound like a reasonable hypothesis?

No. Why, because if this was the case we would expect to see crashes occurring everywhere and all the time. The only way to identify what is happening is to add some debug code to your application so you capture more information prior to the crashes occurring.

Re: AppCrash Issue related to COM?

Tony Tullemans28-Jan-13 11:28

Tony Tullemans

28-Jan-13 11:28

Thanks for your reply Richard, but the problem is that the AccessViolationException very rarely ever occurs when the application is running within the VS development environment, and furthermore it does not occur on all client computers. The only common factors I have been able to establish is that (1) the user has had the program running for several hours, and (2) the user has just switched back to my application after using some other program.

I have come to this forum in the hope that anyone who may have experienced similar errors may give me some clue as to what to look for. I have literally spent over one hundred hours trying to debug this issue.

Re: AppCrash Issue related to COM?

Richard MacCutchan28-Jan-13 22:32

Richard MacCutchan

28-Jan-13 22:32

You have my sympathy, but unfortunately the only way to track this sort of error is to add logging and debugging code to your application. I worked in technical support for many years and often saw problems such as you describe, and yes, they were extremely difficult to diagnose.

Re: AppCrash Issue related to COM?

Stephen Hewitt27-Jan-13 14:13

Stephen Hewitt

27-Jan-13 14:13

That's not how paging works, addresses will be preserved. Get as many crash dumps as you can from the client and start debugging.

Steve

use webbrowser to visit many webs without a break cause crash

BCN-16321-Jan-13 14:52

BCN-163

21-Jan-13 14:52

as the title, I try to use use webbrowser to visit many webs one by one without a break. the memory grows up little by little, finally my program crash down.

I did a lot research, but got little useful information,(somebody said that memory leaks,but I don't know the reason and how to avoid) so I'm here. my code like this.

C++

try
{
	_variant_t vTmp;
	m_webBrowser.put_Silent(TRUE);
	m_webBrowser.Navigate(strWeb, &vTmp, &vTmp, &vTmp, &vTmp);
}
catch (...)
{}

I will call this every 10 seconds continuously. any tips will be appriciate. thanks for your attention.

How to register a com exe without admin rights?

Hari-Adarapu11-Jan-13 9:37

Hari-Adarapu

11-Jan-13 9:37

Hi,

I have a scenario where i should copy and register a com exe but the problem is i don't have admin rights on that pc.

I know that if it is a com dll then using manifest file i can use it without even registering.

Can someone suggest me if there is a way to register com exe without admin rights or use a unregistered com exe using the manifest file?

Thanks in Advance,
Hari krishna

Re: How to register a com exe without admin rights?

Richard MacCutchan12-Jan-13 0:10

Richard MacCutchan

12-Jan-13 0:10

You can use the CoLoadLibrary()[^] function to load and use an unregistered COM library.

One of these days I'm going to think of a really clever signature.

Re: How to register a com exe without admin rights?

Marius Bancila23-Jan-13 10:37

Marius Bancila

23-Jan-13 10:37

I don't think CoLoadLibrary would work with out-of-proc COM servers.

If you don't have admin rights you could probably use registration-free COM activation[^].

Re: How to register a com exe without admin rights?

Richard MacCutchan23-Jan-13 22:48

Richard MacCutchan

23-Jan-13 22:48

You need to tell this to the questioner, not to me.

Re: How to register a com exe without admin rights?

Marius Bancila24-Jan-13 3:07

Marius Bancila

24-Jan-13 3:07

Sorry, for the misunderstanding, it wasn't for you, it was for the OP.

What type of permissions are needed to resolve Acccess denied for GetDsOfNames to registry entry HKCR\Typelib

ForNow7-Jan-13 11:41

ForNow

7-Jan-13 11:41

Hi,

I am getting a ACCESS_DENIED error message when calling GetDsOfNames Here at work I am not looged on as an adminstrator and have no such rights

The support group here wants to know what type of permission I would need

Not having access to the registry and not being all that of expert I dont know what
answer to give

If am running Windows XP Service Pack 3

If anyone can shed some light would appreciate it

Thanks

Re: What type of permissions are needed to resolve Acccess denied for GetDsOfNames to registry entry HKCR\Typelib

Richard MacCutchan7-Jan-13 22:20

Richard MacCutchan

7-Jan-13 22:20

I think you need administrator rights to access HKCR keys. You can check this by running regedit to see if it will start under your userid.

One of these days I'm going to think of a really clever signature.

Creating .OCX file hangs

ForNow1-Jan-13 17:44

ForNow

1-Jan-13 17:44

Hi,

While building a Natiave OLE/COM program build hangs (does not complete) trying to build a .ocx file

IS there anotherway to build the ocx that isn't so time consuming

Thankx

GetIDsOfNames returning -1

ForNow27-Dec-12 12:28

ForNow

27-Dec-12 12:28

Hi,

I am writting a COM app using the MFC wrappers

There are however certain methods/properties which don't have C/C++ prototypes

so I decided to use native OLE functions

I never got by GetIDsOfNames as
what ever method name I insert I get a -1

I have tried native OLE

C++

CoInitialize(NULL);  //native ole
CLSID clsid;         // initialization
HRESULT hr = CLSIDFromProgID(L"Excel.Application",&clsid);

and the MFC wrappers function

C++

_application::CreateDispath

as this method populates

C++

m_lpDispatch

And whatever method property I use I get -1

Any help appreciated

Re: GetIDsOfNames returning -1

Richard MacCutchan27-Dec-12 21:48

Richard MacCutchan

27-Dec-12 21:48

You need to use the GetLastError function[^] to determine why it fails.

One of these days I'm going to think of a really clever signature.

Mixing native OLE with MFC interface/wrappers

ForNow26-Dec-12 15:30

ForNow

26-Dec-12 15:30

Hi,

I have noticed that certain OLE functions dont have MFC wrappers one in particaular Is OpenText

I have noticed also that it seems that for those functions that dont have MFC wrappers, they use a generic AUTOWRAP function

Which is base on native OLE functions
such as IDispatch

I have intlized OLE using MFC/Framework AfxOleInit

to use native ole functions would I have to do intilzations twice

e.g. CoInitlize(NULL) and then CoCreateInstance

I need MFC as I would like use Windows Service in this program

Please Advise

Thanks

Re: Mixing native OLE with MFC interface/wrappers

DriveByCoder24-Mar-15 7:41

DriveByCoder

24-Mar-15 7:41

You don't need to call CoInitialize() again.

You will need to check to see if the MFC interfaces are dual or not. If they are you can use then as if that are non-automation interfaces. I.e. just go

obj->SomeMethod();

My guess is probably not, in which case you will have to use IDispatch->Invoke(...) which is a real pain.
I'm sure you can find helper code out there on the Web.

_WorkSheet::Paste usage

ForNow19-Dec-12 13:01

ForNow

19-Dec-12 13:01

Hi,

I am trying to paste a .txt file onto
an Excel spreadsheet

Off hand it seemed to me the logical
method would be _WorkSheet::Paste

I have done countless google searches
and have yet to come up with C++
exampe of how this method is used

This is the prototype of the method in Excel.h

C++

void Paste(const VARIANT& Destination, const VARIANT& Link);

When I did research on the data type VARIANT the documentation said its a union for many data types

One of them being a LDISPATCH type

The code below is a snipet of the code I have been stuggling with to get the _WorkSheet::Paste method
to work

My logic was to get a LDISPATCH pointer to the range off cells I was trying to paste onto

However I keep on running into exceptions

If anyone could shead some light on this I would be very gratefull

thanks in advance

C++

CI46023App theApp;       // Main CwinThread
_Application app;        // excel application object
_Workbook objBook;       // workbook object 
Workbooks objBooks;      // ditto
Worksheets objSheets;    // worksheet object
_Worksheet objSheet;     // worksheet
LPDISPATCH myrangeptr; 





app.CreateDispatch("Excel.Application");
  objBooks = app.GetWorkbooks();
  objBook = objBooks.Add(VOptional);
  objSheets = objBook.GetWorksheets();
  objSheet = objSheets.GetItem(COleVariant((short)1));
  myrangeptr = objSheet.GetRange(COleVariant(TEXT("A1")),COleVariant(TEXT("M34")));
  objSheet.Paste((VARIANT &)myrangeptr, COleVariant((short)TRUE));

Re: _WorkSheet::Paste usage

Jochen Arndt19-Dec-12 21:45

Jochen Arndt

19-Dec-12 21:45

I'm not quite sure if the Worksheet.Paste method does what you want. It will copy text from the clipboard to the specified (or current) selection (see Worksheet.Paste Method[^]). Setting the second parameter to TRUE will not copy the text but place a link. So if you have copied the text from the file to the clipboard, you may use this function but should pass FALSE as second parameter (or COleVariant((long)DISP_E_PARAMNOTFOUND, VT_ERROR) as optional value which uses the default).

However, the first (also optional parameter) is a range object. Just declare the object, assign the return value of GetRange() and pass it to Paste():

C++

Range objRange = objSheet.GetRange(COleVariant(TEXT("A1")),COleVariant(TEXT("M34")));
objSheet.Paste(objRange, COleVariant((short)FALSE));

Re: _WorkSheet::Paste usage

ForNow20-Dec-12 5:21

ForNow

20-Dec-12 5:21

Hi,

I am at home now but from what I remember when I tried to build the code with VISUAL C++ 6.0 I got a build error saying cannot convert paramter 1 from const struct &VARIANT to class Range The documentation says it accepts a range object as the first parm

but the prototype for the code is Paste(const &VARIANT,

Re: _WorkSheet::Paste usage

Jochen Arndt20-Dec-12 21:04

Jochen Arndt

20-Dec-12 21:04

Sorry, I overlooked the parameter type.

WorkSheet.GetRange() returns a LPDISPATCH which can be assigned to a Range object. You can use the LPDISPATCH returned by GetRange() or access the underlying IDispatch pointer of an existing Range object using the LPDISPATCH() operator to create the required variant:

C++

VARIANT vtRng;
vtRng.vt = VT_DISPATCH;
// Assign LPDISPATCH returned by GetRange()
vtRng.pdispVal = objSheet.GetRange(COleVariant(TEXT("A1")),COleVariant(TEXT("M34")));
// Alternatively, access the IDispatch pointer of an existing Range object
// vtRng.pdispVal = objRange;
objSheet.Paste(vtRng, COleVariant((short)TRUE));

MSDN documentation for MFC OLE wrapper method/prperties

ForNow17-Dec-12 13:10

ForNow

17-Dec-12 13:10

Hi,

First off I like to thank Richard MacCutchan with helping in setting up my C++ project to generate the MFC OLE wrappers classes

One strange thing unlike the regualar MFC classes CWinThread, CDialog

There doen't seem to be any MSDN docmentation about any of the methods in the wrapper classes

One can only guess by thier name what they do

thanks

Re: MSDN documentation for MFC OLE wrapper method/prperties

Richard MacCutchan17-Dec-12 22:19

Richard MacCutchan

17-Dec-12 22:19

See here[^].

One of these days I'm going to think of a really clever signature.

Re: MSDN documentation for MFC OLE wrapper method/prperties

ForNow18-Dec-12 2:28

ForNow

18-Dec-12 2:28

Hi,

I am finally begining to understand why the Microsoft article said I should create dialog based ontrol as a MFC app needs a main window

I tried to follow the article in creating the project but I wa a bit confused what the srticle meant by changing the IDOK button IDCRUN

I ended up getting some sort of exception when existing Cdialog::Initinstance I beleive it be a invalid Hwnd for the Dialog

COnceputally then the Excel spread sheet is a control with the Cdialog being the mainwindow

Richard the doumentation you pointed me to was about Wrapper classes as MFC frontends the OLE functions

I was looking for documentation of the type Cdialog::GetDefID in native MFC there would be documentation for Range::SetValue for the wrapper classes

Thanks again

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