Equivalent C statement for VB Set

[cksiow]

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

[Vi2]

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

[cksiow]

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

[Vi2]

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

[cksiow]

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


HTH

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

[Vi2]

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