VC ATL, passing COM object pointers to another COM object in ATL

passing COM object pointers to another COM object in ATL

Author	Message
Sujit Vasud #1 / 5	passing COM object pointers to another COM object in ATL hi, I have a COM object having a member pointer variable pointing to a C++ object. I want to create another COM object with a method that accepts the first COM object as a parameter. I tried using VARIANT, but the pointer variable in the passed object comes in as NULL (though, the pointers were initialized before being passed). It works fine if I use IUnknown* or IDispatch; but then I am not able to use the parameter as "optional" when calling from VB (it throws a type mismatch if I dont pass an argument to an optional parameter of type IUnknown or IDispatch*). Any ideas why this is happening? Any solutions?
Fri, 04 Jun 2004 19:32:12 GMT

zhuxifen #2 / 5	passing COM object pointers to another COM object in ATL Quote: > hi, > I have a COM object having a member pointer variable pointing to a C++ > object. I want to create another COM object with a method that accepts > the first COM object as a parameter. > I tried using VARIANT, but the pointer variable in the passed object > comes in as NULL (though, the pointers were initialized before being > passed). > It works fine if I use IUnknown* or IDispatch; but then I am not able > to use the parameter as "optional" when calling from VB (it throws a > type mismatch if I dont pass an argument to an optional parameter of > type IUnknown or IDispatch*). > Any ideas why this is happening? Any solutions?
Fri, 18 Jun 2004 13:58:22 GMT

Alexander Nickolo #3 / 5	passing COM object pointers to another COM object in ATL So did you store IUnknown or IDispatch in that VARIANT? Did you AddRef it? Did you set the vartype to VT_UNKNOWN or VT_DISPATCH respectively? -- ===================================== Alexander Nickolov Microsoft MVP [VC], MCSD MVP VC FAQ: http://www.mvps.org/vcfaq ===================================== Quote: > > hi, > > I have a COM object having a member pointer variable pointing to a C++ > > object. I want to create another COM object with a method that accepts > > the first COM object as a parameter. > > I tried using VARIANT, but the pointer variable in the passed object > > comes in as NULL (though, the pointers were initialized before being > > passed). > > It works fine if I use IUnknown* or IDispatch; but then I am not able > > to use the parameter as "optional" when calling from VB (it throws a > > type mismatch if I dont pass an argument to an optional parameter of > > type IUnknown or IDispatch*). > > Any ideas why this is happening? Any solutions?
Mon, 21 Jun 2004 04:27:49 GMT

#4 / 5	passing COM object pointers to another COM object in ATL
Fri, 19 Jun 1992 00:00:00 GMT

Zolo #5 / 5	passing COM object pointers to another COM object in ATL Could you please send me a piece of your code. I am trying to do the same but I have no sample code Thank you by advance.
Tue, 22 Jun 2004 04:09:36 GMT

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