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If I didn't misunderstand you
static HRESULT CComObject<Base>::CreateInstance(CComObject<Base>** pp)
should be the solution to your problem.
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Any sample or link to a tutorial?
Thanks!
Daniel 
---------------------------
Never change a running system!
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Hello Daniel,
I created a sample ATL project with two simple coclass's (Test and Test2). One of them, Test2 is specifically noncreatable. This noncreatble feature can be set easily by including the "noncreatable" attribute for the coclass statement in the IDL file :
[
uuid(A6C64958-F337-4981-8F31-F35AEA02DD98),
helpstring("Test2 Class"),
noncreatable
]
coclass Test2
{
[default] interface ITest2;
[default, source] dispinterface _ITest2Events;
};
This attribute is very useful when your client apps are Visual Basic based. In VB, if a coclass is noncreatable, then when you attempt to create a new instance of it via the "New" keyword, e.g. :
Dim Test2Obj As Test2
...
...
...
Set Test2Obj = New Test2
You will get an error message that reads : "Invalid use of New keyword".
However, the "noncreatable" attribute is not sufficient for VC++ clients. In a VC++ client app, if you have the following statement :
ITest2Ptr spTest2Ptr = NULL;
spTest2Ptr.CreateInstance(__uuidof(Test2));
Surprise, surprise, you will still succeed and obtain an ITest2 smart pointer.
In order to ensure that the above CreateInstance() function call will fail, you will need to comment out the Test2 Object Entry in the ATL Object Map of your ATL project :
BEGIN_OBJECT_MAP(ObjectMap)
OBJECT_ENTRY(CLSID_Test, CTest)
//OBJECT_ENTRY(CLSID_Test2, CTest2) <-- comment out this line.
END_OBJECT_MAP()
This will ensure that when your ATL DLL is asked to create an instance of an object of coclass Test2 (this happens in the global DllGetClassObject() function), a failure code will be returned.
Note that the good thing about the "noncreatable" attribute and the commenting out of the OBJECT_ENTRY statement will not prevent you from internally creating the CTest2 object. This is, of course, required when the GetInterface() method is called. My implementation of GetInterface() is as follows :
STDMETHODIMP CTest::GetInterface(int n, ITest2 **pITest2)
{
// TODO: Add your implementation code here
CComObject<ctest2> *pTest2New = NULL;
CComObject<ctest2>::CreateInstance(&pTest2New);
if (pTest2New)
{
pTest2New -> QueryInterface (IID_ITest2, (void**)pITest2);
}
return S_OK;
}
I will email you the sample source codes plus VB and a VC++ client apps.
Hope the aboe info will help.
Best Regards,
Bio.
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Hello Daniel,
Please email me your email address so that I can send to you some sample codes.
Best Regards,
Bio.
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Thanks! It works fine!
Cheers,
Daniel.
--
FIND A JOB YOU LOVE, AND YOU'LL NEVER HAVE TO WORK A DAY OF YOUR LIFE.
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I add an interface to an OCX,
when I use the OCX, it throw an exception and pop a message box "parameter not optional".
Why? who can tell me reason?
Thanks a lot!
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Are you passing a VT_EMPTY or a VT_NULL?
Well, you shouldn't 
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Just my 2 cents:
On insertion your OCX maybe querying container for some ambient property not supported by your container.
"...Ability to type is not enough to become a Programmer. Unless you type in VB. But then again you have to type really fast..."
Me
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I have an out-of-proc COM server. In one of the method of my COM server, I need Thread Id of the client application who is calling the method. Is there any way to get thread id fo client process in COM server code?
Regards.
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One solution is to require the client to pass in its ID as one of the parameters.
Kuphryn
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You are right, but this is not a solution for the problem. I was looking for an API to get thread id of COM client.
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There is no such API to my understanding. If the client does not provide the server with more information, then there is nothing linking the them except for the pointer that the client holds and the reference count on the server-side.
Kuphryn
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Is there a way (free, not commercial programs) to detect un-released COM
interfaces? I use alot of CComPtr and also regular interfaces and I want
to make sure that there are no problems with reference counting.
thanks
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I guess you already use
_ATL_DEBUG_INTERFACES and _ATL_DEBUG_QI?
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Actually it's the first time I hear about those defines. But
aren't those for use in ATL projects? Besides, I tried searching
them in MSDN (web site) and found nothing.
Can you briefly explain what they do?
thank you
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Ok, now you got me confused... You use CComPtr and don't use ATL?
Anyway, define those two and watch your debug output...
(To see how they work use the great "Goto definition" in the IDE.)
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These macros are in atl based macros, so i'll need to do some work before
i can get them to work.
Why, can't I use CComPtr without ATL? Why not?
anyways, thanks alot. It's certainly a step in the right direction.
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Oh, CComPtr is now shared with MFC.
*DOH* I should have figured that out.
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well, actually it's not a MFC project neither.
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Dear Sir,
I am new to COM/DCOM and looking for some good books/web site to understand the COM/DCOM . I am also looking for information about the difference in COM , OLE , ActiveX etc . After understanding COM concept , I want to develop COM components using VB and VC++
Kindly suggest some good books/websites to learn these concepts and programming practices .
With thanks and regards
B Mittal
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I highly recommend Developer's Workshop to COM and ATL 3.0 by Andrew Troelsen.
Kuphryn
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please give the internet address out
dupengfei
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That would be tricky, since it's a printed book.
Steve S
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how to know that the view of an activex control has changed?
thanks
regards
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