Equivalent C statement for VB Set

in VB, we can set a variable reference to another variable, like this

dim d as new class1
dim withevents c as class1

set c = d

so, c is not an instance, but rather reference to d, but whenever, some event happen in d, c get triggered.

So, what is the equivalent C statement for "set c = d" ? thanks.


HTH

cksiow
http://vblib.virtualave.net - share our codes

Your question actually contains 2 questions: with and without "WithEvents"
1.

dim d as class1
dim c as class1
set c = d



are equivalent the origin assignment of object pointer

CComPtr<IClass1> spd;
CComPtr<IClass1> spc;
spc = spd;



2.

dim d as class1
dim withevents c as class1
set c = d



are equivalent the origin assignment of object pointer and connection to object

CComPtr<IClass1> spd;
CComPtr<IClass1> spc;
spc = spd;
// Here should be the CComPtr<IClass1>::Advise to connect to stored object with Event Sink pUnk
// CComPtr<>::Advise(IUnknown* pUnk, const IID& iid, LPDWORD pdw)





With best wishes,
Vita

thanks. but i don't intend to use ATL, can u change to following statement to C++ statement, assuming my interface is call IClass1

CComPtr<IClass1> spd;CComPtr<IClass1> spc;spc = spd;

thanks again.



HTH

cksiow
http://vblib.virtualave.net - share our codes

There are too many techniques.

IClass1* d;
IClass1* c;



1.

c = d;
c->AddRef();
...
c->Release();



2.

HRESULT hr = d->QueryInterface(IID_IClass1, static_cast<void**>&c );
if( SUCCEEDED(hr) )
{
...
c->Release();
}



and so on. But it's good idea to use the wrappers of the interface pointers (CComPtr, smart-pointers etc.).

With best wishes,
Vita

for the Advise, how do we get the sink pUnknown ? thanks.


HTH

cksiow
http://vblib.virtualave.net - share our codes

For the Advise, you must create the sink COM object (realizing of class1's event interface) and get its IUnknown interface to Advise() function.
For example, ATL realization of this technique:

ATLINLINE ATLAPI AtlAdvise(IUnknown* pUnkCP, IUnknown* pUnk, const IID& iid, LPDWORD pdw)
{
CComPtr<IConnectionPointContainer> pCPC;
CComPtr<IConnectionPoint> pCP;
HRESULT hRes = pUnkCP->QueryInterface(IID_IConnectionPointContainer, (void**)&pCPC);
if (SUCCEEDED(hRes))
hRes = pCPC->FindConnectionPoint(iid, &pCP);
if (SUCCEEDED(hRes))
hRes = pCP->Advise(pUnk, pdw);
return hRes;
}



where pUnkCP - IUnknown of Server object (class1 for you, either c or d object),
pUnk - IUnknown of Sink object
iid - IID of class1's event interface
pdw - cookie to Unadvise()

With best wishes,
Vita