a COM+ design question - COM Discussion Boards

Ranjan Banerji20-Dec-02 5:44

20-Dec-02 5:44

Yes it is possible. Not sure what the cause of the error is, but most likely it is coming from something in INewParentClass. An ATL based class can inherit from a regular C++ class, not another ATL class.

Re: ATL COM thingie using inheritance

pba_23-Dec-02 12:30

pba_

23-Dec-02 12:30

Probably INewParentClass is inherited from IDispatchImpl too.

Beginners help with SAFEARRAY

Obliterator19-Dec-02 8:24

Obliterator

19-Dec-02 8:24

Hi all,

I have what seems to be a trivial problem...
I need to convert an array of doubles to a SAFEARRAY**

i.e. I have:
double MyArray[50];

I need to pass this to a third part function as a SAFEARRAY**

I'm sure this is a doddle - but I just keep crashing it with what I pass.
I'm new to all this COM stuff... why does it have to be so complicated?!

Thanks

--

The Obliterator

Re: Beginners help with SAFEARRAY

Barry Lapthorn19-Dec-02 20:47

Barry Lapthorn

19-Dec-02 20:47

Something like this should help:

SAFEARRAY* CFoo::DoubleArrayToSafeArray(double* array, int n)<br />
{<br />
        // n is the size of the array.<br />
        // caller takes ownership of returned SAFEARRAY<br />
<br />
        // create array bounds.<br />
	SAFEARRAYBOUND rgsabound[1];<br />
	rgsabound[0].lLbound = 0;<br />
	rgsabound[0].cElements = n;<br />
<br />
        //  create safearray<br />
	SAFEARRAY* pReturn = NULL;<br />
	pReturn = SafeArrayCreate( VT_R8 , 1, rgsabound);<br />
<br />
	if (pReturn == NULL)<br />
		return pReturn;<br />
<br />
        //  populate it<br />
	long idxPos = 0;<br />
	for (idxPos = 0 ; idxPos < n; idxPos++)<br />
	{<br />
	  HRESULT hr = SafeArrayPutElement(pReturn, &idxPos, (void*) &(array[idxPos]));<br />
	}<br />
	return pReturn;<br />
}

Regards

Barry

Re: Beginners help with SAFEARRAY

work_to_live20-Dec-02 20:18

work_to_live

20-Dec-02 20:18

Barry,
Can you point me to a good overview on the use of SafeArrays and Variants?

Thanks.

Re: Beginners help with SAFEARRAY

Barry Lapthorn22-Dec-02 0:37

Barry Lapthorn

22-Dec-02 0:37

I spent ages trawling through MSDN I'm afraid. Frown | :(

I would imagine that there are some articles on safearrays and variants here on CodeProject as well. Big Grin | :-D

Regards

Barry

Re: Beginners help with SAFEARRAY

Barry Lapthorn23-Dec-02 3:16

Barry Lapthorn

23-Dec-02 3:16

Try:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnguion/html/drgui032999.asp[^]

and

http://support.microsoft.com/support/kb/articles/Q167/6/68.ASP[^]

Regards

Barry

a COM+ design question

Anonymous19-Dec-02 3:16

Anonymous

19-Dec-02 3:16

I want to design a card game ,use Com+ server.
But when 4 clients connected,it's created 4 com+ instance in server,
so it's hard to manage.
I want to know :
how I can connect every 4 clients to 1 com+ instance in server.

Re: a COM+ design question

Burt Harris21-Dec-02 10:34

Burt Harris

21-Dec-02 10:34

Hi Anonymous,

I'm not sure use of COM+ for this is a good match betwen your problem and the platform. You might want to take a look at DirectPlay http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dx8_c/directx_cpp/Play/DPlay.asp[^] which is specifically designed for multi-player games.

Burt Harris

Got CLSID/PROGID, how to access?

Anonymous19-Dec-02 1:25

Anonymous

19-Dec-02 1:25

Hi,

I've got a CLSID for a COM object in a C++ program, how do I access methods on this object. Do I have to call QueryInterface() somehow?

I can do a CoCreateInstance() but that requires an interface ID. Assuming all I have is the CLSID, how do I do it?

Thanks!

Re: Got CLSID/PROGID, how to access?

Anonymous19-Dec-02 10:17

Anonymous

19-Dec-02 10:17

Try to QI for IUnknown or IDispatch

CLSID clsid;//some valid clsid
LPDISPATCH pDisp;
HRESULT hr = CoCreateInstance(clsid,NULL,CLSCTX_SERVER,IID_IDispatch,(LPVOID*)&pDisp);
if(SUCCEEDED(hr))
{
//now call interface methods
pDisp->AutomationCall();
}
}

Re: Got CLSID/PROGID, how to access?

geo_m30-Dec-02 6:16

geo_m

30-Dec-02 6:16

hmm, in fact, you can create the object, asking CoCreateInstance for IID_IUnknown as an Interface ID (IID). Then you will receive the pointer to the IUnknown.

But the question is what you want to do next - for nearly every other activity you will need to retrieve some interface from the object, else you will be able only to call IUnknown methods or might be IDispatch methods, but without any further info you are generally not able to perform any operation over that object.

I don't know if I expressed myself correctly, but the situation then is similar to having a .lib without header - so you have some objects inside the lib but you don't know how to talk to them.

What interface to implement to be a datasource to VB data bound control?

Erik Juhl13-Dec-02 5:47

Erik Juhl

13-Dec-02 5:47

I have created a COM collection object for use by our UI team, but now requirements seem to have changed and they no longer want COM collections but something like ADO recordsets they can bind to their grids. It seemed to me that a data bound control is probably just using an interface on the ADO recordset objects to navigate the collection. And since I already had my COM collection implemented, if I could implement this mysterious DataSource interface I could make everyone happy. Can anyone give me a push in the right direction? What interface do I need to implement in my COM collection to act as a DataSource for a VB Data Bound control? Thanks in advance.

Re: What interface to implement to be a datasource to VB data bound control?

Jörgen Sigvardsson24-Dec-02 12:46

Jörgen Sigvardsson

24-Dec-02 12:46

Take a look at the ATL OLEDB data producer classes¹. Many grids support OLEDB as well if I'm not mistaken..

Just fire up an ATL project, and add an OLEDB data producer class using the ATL wizard, and go on from there. Smile | :)

¹ I'm not sure this is the correct name. I'm 100 miles from home, so I can't lookup the name right now. But just look at the ATL wizards and you'll know it when you see it.

--
Only in a world this sh*tty could you even try to say these were innocent people and keep a straight face.

how to debug visual com dll ??

Leesen13-Dec-02 5:08

Leesen

13-Dec-02 5:08

hi,all
I write a COM Dll in Visual ATL . And I refer the COM dll in VB environment. The vb program runs well except when the program exit, the error dialog occur. The error info are such as "the address can't read ..." . Is it concerns with
the c++ pointer ??? But how can I find the actuall false??

Are there any tools to help to debug the com dll??
The problem disturb me for very long time .

Ask for your help , please !

Regards.

Re: how to debug visual com dll ??

geo_m13-Dec-02 11:29

geo_m

13-Dec-02 11:29

Best way is to load the ATL project to the MSVC and set up the visual basic as a startup exe. Then when you press f5, the VB will be started. You can work with the VB as you want, e.g. load some test project, but you can put the breakpoints to methods of your DLL and the execution will stop there in case it will be called...

Re: how to debug visual com dll ??

Leesen13-Dec-02 16:08

Leesen

13-Dec-02 16:08

hi,

thx.
I can debug the com dll following your advice.
Because just when my vb program exit the errors occurrs,
I set breakpoints in destructor function . Then when I exit the vb program ,it seemed the program did not execute the destructor code. It did not pause on the breakpoints,instead there showed a error dialog "Unhandled exception in P2P.exe : Access Violation".
If I direct run the vb program without the debug mode , when I exit the vb program I will receive such error message"the memory address can't be read..."

why?? I am exhausting now after so much try.
thx.
regards.

Re: how to debug visual com dll ??

geo_m14-Dec-02 4:13

geo_m

14-Dec-02 4:13

Hi,

well have not exactly an idea, only what I would check very carefully are the circular references in VB. I think, that the similar things happened to me some time ago, when I 'developed' a circular reference through three objects and the VB garbage collector didn't detect it and failed on some exception.

What can be next thing is some topics similar to it - returning a pointer to memory which is later freed inside the component (normally one should return a copy of the memory, because VB will release it later) and similar thingiez.

In short, first who will be suspect for me in such a case will be the VB garbagge colector.

Re: how to debug visual com dll ??

Leesen17-Dec-02 13:22

Leesen

17-Dec-02 13:22

hi
But how can I solve this problem . You know ,anyway ,if the program have such a bug ,my boss will not be satisfactory with me. I have try many times these days, but failed.

Can you give me some advice on how to resolve this problem. It'll be appreciated.
thx.

regards.

Re: how to debug visual com dll ??

geo_m19-Dec-02 2:20

geo_m

19-Dec-02 2:20

Yeah. Bosses are allways the same. Anyway, this is very difficult question. It depends on the program design. Normally I am checking nearly everything regarding all return values especially returning some memory structures (BSTR, VARIANTS, arrays...). Also I am checking the dependencies and ownerships you can sometimes see, that object A points to object B and object B points to object C while C points to A - this is exactly the situation where VB garbagge collector crashes. Good luck!

WebBrowser text is not updated after Replaying Keypress event

p_khasnis12-Dec-02 15:53

p_khasnis

12-Dec-02 15:53

Hello,

I am trying to replay a set of recorded events in WebBrowser. I am able to record and replay the events like keypress and click events on the html page displayed in the browser.

However, when i am replaying events like keypress into a text box and then a click on submit button, the application does play the events but i am not able to see the text entered inthe text box on the HTMl page.

Similarly if there more text boxes and events are replayed on them then the text is seen only after the function for replaying of events returns.

for e.g. Google's page has a textbox and Google search button. If i just record events in the text box without clicking on search and replay them back i am able to see the text in the textbox after the replaying is complete. However if i also press click on the search button and try to replay these two events then the app puts the text and clicks the button and navigates to result page and thus the events are replayed properly, but the text is not seen in textbox before navigation.

Further info:
I am using WebBrowser in VC++ and IHTMLDocument2 pointer. With this i am able to get the HTML of the element and compare it with the recorded event's HTML. When i find the element(IHTMLElement) i use either a click() or put_innexText() api's depending on whether it was a click or a keypress event.

I have tried to run the function which replays events in OnDocumentComplete(), directly and then again inside a thread so as not to interfere with the documentcomplete process. I have also tried to use sleep in OnBeforeNavigate().

Secondly, I have tried to use PostMessage and SendMessage and keybd_event() apis to see if they make any difference. All this has failed.

Please somebody help me with this. Thanks in advance.

Regds,
Prasad.

Prasad
Thanks again

Re: WebBrowser text is not updated after Replaying Keypress event

geo_m12-Dec-02 23:49

geo_m

12-Dec-02 23:49

modified, after read it completely Wink | ;)

. just a wild shot - maybe IE needs some time to refresh it's window, or, this might depend on the app design, somehow during the playback, the IE window messages are not handled or something like that (this can be specially if your player is an inprocess component and it seems to me that it is).
If I looked to furhter info, it looks to me so, that you fill the textboxes or whatever, but there is no time to display it.
What I will try on your place is to process the messages after each change (PeekMessage, DispatchMessage...). This might help

Re: WebBrowser text is not updated after Replaying Keypress event

p_khasnis13-Dec-02 2:17

p_khasnis

13-Dec-02 2:17

Thats right IE basically is not updating the component after the text is entered. It does have the time to update it. I am iterating through a linklist picking up events and then firing them, so i just need to get out of that loop. Say for eg by displaying a dialog box.

I have currently solved this problem by using postmessages and sleep in my dll.

Thanks anyway, I will try to check out ur solution too and let u know.

Prasad
Thanks again

COM+ and SetUnhandledExceptionFilter

AboMalek10-Dec-02 3:06

AboMalek

10-Dec-02 3:06

Hi All,
I'm trying to set a top-level exception call-back filter inside a com+ application server.
Although SetUnhandledExceptionFilter seems to succeed, that it returns the previously installed filter correctly, my filter never been called.
of course I'm trying to detect the call in a (release mode) through a simple code that creates a log file to be filled later with the proper informations I need for recovering.When calling the filter from a __try/__except(MyFilter(..)) block, the filter code executes correctly, but when generating a purposly unhandled exception the file is never been created.
Any idea?

Regards.

AbuMalek

how to save the ppt to html??

zhaosd9-Dec-02 0:11

zhaosd

9-Dec-02 0:11

hi,i am trying to save the ppt file into html,
and i call "saveas" to do it,but if the ppt file
is bigger ,it very slow!! how to make it faster??

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