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c++windowsvisual-studiocomvb6

How to load COM DLL at runtime

I have a VB6 COM DLL. I want to use it from C++. I know how to register it, generate a tlb file from the DLL, and #import it in C++.

I'd like however, to load and use DLLs like this dynamically, at runtime, without knowing them in advance. Is this possible?

Thanks,

Solution

  • Yes, but you need to get the question clearer.

    Sometimes, you do know the COM interface upfront, just not the implementation. In that case, you can create a dummy implementation of the interface and #import that. At runtime, you'd still register the real component, get an object from it (via CoCreateInstance probably) and store that in an appropriate smart pointer.

    With VB6, it's a bit less direct. This adds a level of indirection. Read up on IDispatch. You need to get that known interface to describe an unknown interface. That way, the unknown interface can be obtained at runtime.