Question and Answer Database FAQ4510C.txt — How do I talk to an Visual Basic ActiveX control. Category :ActiveX Platform :All-32Bit Product :C++Builder3.x, C++Builder4.x, Question: I imported a control made with Visual Basic. When I call one of it's methods I get an Access Violation. Why? Answer: All of the published books on COM will tell you that the interface is laid out like a C++ virtual base class --- that is to say, it is safe to assume that the function pointers are placed sequentially in a table. VB produces "sparse vtables", which is to say, their function pointers are _not_ laid out sequentially in a table. You have to use Ole Automation(IDispatch) instead of vtable support. We are aware of the problem, and working to fix it. 3/29/99 3:49:47 PM
Last Modified: 01-SEP-99