Re: using BSTR - COM Discussion Boards

Stephen Hewitt19-Dec-06 18:25

19-Dec-06 18:25

Is it a COM dll? You can check this with OLEView or look to see if it exports the normal COM functions. If so you need to generate a RCW[^] (Runtime Callable Wrapper) for the DLL. I'm not a dotNET programmer so I can't help you with the specifics.

Steve

create a process using WMI?

abhiramsss18-Dec-06 8:55

abhiramsss

18-Dec-06 8:55

hi all
how to create and terminate a process using WMI

Can i have c++ code for it

Thanks

abhi

Starting COM Client from script

Manfred Staiger218-Dec-06 2:37

Manfred Staiger2

18-Dec-06 2:37

Hello everybody,
I have a COM client application which connects to COM server on the same machine. Everything works fine. But when I start the client from an asp script, the call to CoCreateInstance fails for some reasons. I`m not very experienced in COM programming. Do I have to use CoCreateInstanceEx because the client runs in the context of the webserver when it is started from the script? Or whatelse could be the reason? Does anybody have an idea?

tree view problem?

sajid.salim.khan16-Dec-06 8:15

sajid.salim.khan

16-Dec-06 8:15

Hi All
whats the best way if a treeview node is associated with 3 values more easily i say that when click on the node 3 values are displayed in Listview for that node how to bind the values with that particular node

SAS Rose | [Rose]

Re: tree view problem?

User 21559718-Dec-06 1:07

User 215597

18-Dec-06 1:07

wrong forum. I think your question is not related to COM. Try VC++ forum to get correct and fast answer.

S o h a i l K a d i w a l a

To Err Is Human; to Debug, Divine

modified 21-Apr-21 21:01pm.

using BSTR

chrigi00115-Dec-06 3:15

chrigi001

15-Dec-06 3:15

Hi
First: I know there are many topics in codeproject about using BSTR but i cant help myself further after 2 days trying to solve this problem...

1) Situation
============
My task is to write a program in VC++ which makes a windows program communicate to a sensor (MTi). There is a fully functional command line program from the producer of the sensor. Now i want to change severel settings (using specific functions) of the sensor like sample frequency and so on. The main function makes a Motion Tracker Object (written in c) to realize the communication through a virtual COM Port.

2) Problem
==========
I want to change the sample frequency of the data exchange between the program and the sensor (default it is 100Hz which is to fast for my application):

<br />
int nSFreq=25; //Sample Frequency in Hz<br />
int nUSFreq=0; //Used sample Frequency<br />
//Set new sample Frequency where pMT is the created Motion Tracker Object<br />
pMT->MT_SetMotionTrackerSampleFrequency(nSFreq);<br />
//Show the Sample Frequency for checkup <br />
MT_GetMotionTrackerSampleFrequency(&nUSFreq);<br />
//Show it on command Line<br />
printf("Your sample Frequency %d", nUSFreq);<br />

--> the command line shows 25 as expected, but the sensor samples still with 100Hz. Now i read that i have to safe the settings on the sensor using the sensor ID which is a BSTR. The ID i can get from this function:

<br />
//get the device ID<br />
virtual HRESULT STDMETHODCALLTYPE MT_QueryMotionTrackerB(<br />
            /* [out] */ BSTR __RPC_FAR *bstrDeviceID) = 0;<br />
//safe the new settings trough this function<br />
virtual HRESULT STDMETHODCALLTYPE MT_SaveToMTS( <br />
            BSTR bstrDeviceID) = 0;<br />

--> now, what i have done in my program:

<br />
BSTR nDId;<br />
//get the Device ID<br />
pMT->MT_QueryMotionTrackerB(&nDId);<br />
//safe settings<br />
pMT->MT_SaveToMTS(nDId);<br />

-->The program compiles very nice but when i run the .exe i got this damn error message all the time:
"An exception 'System.NullRefereceException' has occured in MTi.cmd1.exe"
(-->The error is only caused when i use the BSTR function shown above)

I know the problem is this BSTR but i cant help myself. Maybe someone can tell me what i need to do.
1000Thx

chris

Re: using BSTR

lafleon15-Dec-06 8:51

lafleon

15-Dec-06 8:51

Hi,

Just use CComBSTR instead of BSTR and use CString to convert from BSTR to char* and visa versa.

Regards

Re: using BSTR

prasad_som15-Dec-06 19:14

prasad_som

15-Dec-06 19:14

chrigi001 wrote:
-->The program compiles very nice but when i run the .exe i got this damn error message all the time:
"An exception 'System.NullRefereceException' has occured in MTi.cmd1.exe"
(-->The error is only caused when i use the BSTR function shown above)

Problem may not be with BSTR as you think. Can you check if MT_QueryMotionTrackerB gives value correctly. Or which function of them is giving exception.

chrigi001 wrote:
"An exception 'System.NullRefereceException' has occured in

Generally, this exception occurs due to accessing NULL pointer as it indicates. See by placing checks at places wherever you can.

Prasad
Notifier using ATL | Operator new[],delete[][^]

How to debug

skylarmei14-Dec-06 15:52

skylarmei

14-Dec-06 15:52

Please tell me how to debug in add_ins;There is some problem in my programme,but i not know how to debug it ;please help!

Re: How to debug

Anton Afanasyev14-Dec-06 16:06

Anton Afanasyev

14-Dec-06 16:06

Sorry, we dont lease help here Big Grin | :-D

Badger | [badger,badger,badger,badger...]

Re: How to debug

skylarmei14-Dec-06 16:10

skylarmei

14-Dec-06 16:10

sorry

Re: How to debug

prasad_som16-Dec-06 0:01

prasad_som

16-Dec-06 0:01

You need to give host exe's path to debug your add-in. And put break point in connecting function of your add-in. i.e. function through which add-in and host application communicate. And follow usual debugging technique.

Prasad
Notifier using ATL | Operator new[],delete[][^]

Calling an executable from Internet Explorer as a script? [modified]

ghost120713-Dec-06 22:30

ghost1207

13-Dec-06 22:30

Hi all,

I am not too sure where to post my question, so I'll just put it here and hope that somebody will help me. Honestly, I've reached a deadend after searching ALOT. I'll greatly appreciate any help or indication.

The problem:
In Internet Explorer you can right-click on a page and hit "Export to Microsoft Excel". This command is set in the registry (HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\MenuExt\Export to Microsoft Excel) to call Excel with "EXCEL.EXE/3000".

The purpose:
I would like to develop a executable with simular functionality: the ability to be called from the internet explorer.

The question:
What is the technology that excel is using? Is it a COM object implementing an interface? How do I do that in .NET? And what on earth is that "/3000" parameter?!?

I've been looking for an answer for quite some time now. Please help.

Rgds,
G.

-- modified at 5:36 Thursday 14th December, 2006

Re: Calling an executable from Internet Explorer as a script?

mejax13-Dec-06 23:00

mejax

13-Dec-06 23:00

Did you browse through
http://msdn.microsoft.com/workshop/browser/ext/extensions.asp

_________________________

"When the superior man refrains from acting, his force is felt for a thousand li." Sun Tzu

Re: Calling an executable from Internet Explorer as a script?

ghost120713-Dec-06 23:17

ghost1207

13-Dec-06 23:17

Yeap! There is an article there called "Adding Entries to the Standard Context Menu", which is relevant with the case, but unfortunately it doesn't mention anything about how the executable should be made (i.e. what interfaces should implement, how they are exposed etc).

Note that the whole thing works if I set the right-click to call a javascript htm page, but not if I call an executable.

..and I am very curious to find what this "\3000" param is..

Re: Calling an executable from Internet Explorer as a script?

Colin Angus Mackay13-Dec-06 23:15

Colin Angus Mackay

13-Dec-06 23:15

Given the big red text that says "Do not post programming questions (use the programming forums for that)" why did you think posting it here would be a good idea?

Your post in the C# forum was a better choice.

Upcoming Scottish Developers events:
* Glasgow: Tell us what you want to see in 2007

My: Website | Blog | Photos

Re: Calling an executable from Internet Explorer as a script?

JacquesDP13-Dec-06 23:23

JacquesDP

13-Dec-06 23:23

And if you look here and then in the C# forum, the lounge has given him more feedback than the C# forum Laugh | :laugh:

He who laughs last is a bit on the slow side

Re: Calling an executable from Internet Explorer as a script?

ghost120713-Dec-06 23:24

ghost1207

13-Dec-06 23:24

I apologize for this. I saw the text only after I hit the "send" button (too overwhelmed with the issue I guess Dead | X|

)

Strange enough, though, I got an answer from this thread instead of the "C#" one!

Re: Calling an executable from Internet Explorer as a script?

Colin Angus Mackay13-Dec-06 23:30

Colin Angus Mackay

13-Dec-06 23:30

ghost1207 wrote:
Strange enough, though, I got an answer from this thread instead of the "C#" one!

Maybe, but you've irritated people in the process.

Upcoming Scottish Developers events:
* Glasgow: Tell us what you want to see in 2007

My: Website | Blog | Photos

PowerPoint Shape Export

Topsen13-Dec-06 21:35

Topsen

13-Dec-06 21:35

Hallo,

I want to export the objects on a powerpoint-slide via office automation.
I use Visual Studio .NET 2005 an Office 2003. When I try the funktion

Shape.Export(filename, PowerPoint.PpShapeFormat.ppShapeFormatGIF, width, height, PowerPoint.PpExportMode.ppClipRelativeToSlide);

i get the images, cliparts, etc.. But they don´t have the specified width and height.
The Dimension of the Shapes differs in horizontal and vertical dpi. How can I set correct DPI-sizes and Pixel-sizes?

Thx,

Tobias

Determine virtual function table size

J.B.13-Dec-06 17:21

J.B.

13-Dec-06 17:21

Hi all,

I am wondering if it is possible to determine the size (or number of valid function entries) of a virtual function table using the queried interface pointer.

Say I obtained an interface pointer pIMyvia QueryInterface:

pIBase->QueryInterface(&IID_MYINTERFACE, (void**)&pIMy, hr);

I was able to cast the pIMy to vtable pointer pVTable and access each each function's address value with pVTable[0], pVTable[1]..etc. And obviously sizeof(pVTable) returns 4 instead of size of the vtable.

Any ideas how it is possible to determine the size virtual function table?

Thanks in advance,
J.B.

Re: Determine virtual function table size

Roger Stoltz13-Dec-06 21:54

Roger Stoltz

13-Dec-06 21:54

Perhaps there's a trick that I'm not aware of, but I don't think you can get the size of the vtable in runtime.

If you create an interface that inherits from IUnknown, the first 12 bytes of the vtable will be the addresses of QueryInterface(), AddRef() and Release(). The next four bytes will contain the address of the first method for the new (child) interface and so on until the vtable is complete. The bytes following the vtable will contain data for the member variables, there's no "padding" or "termination" of the vtable, hence I don't think you can tell the size of it in runtime. Perhaps there's a trick when building for 'Debug', but I don't think so.

On the other hand: why do you want to know the size of the vtable? Confused | :confused:

Perhaps there's another solution for your problem.

--
Roger

"It's supposed to be hard, otherwise anybody could do it!" - selfquote

"No one remembers a coward!" - Jan Elfström 1998
"...but everyone remembers an idiot!" - my lawyer 2005 when heard of Jan's saying above

DLL hell

rockyl12-Dec-06 3:15

rockyl

12-Dec-06 3:15