Comments by egon_ll (Top 9 by date)

Thank you! Now it works.

This can not work, as LightControl is only defined in the dll but not in the program calling the dll.
I tried it anyway and I get the error "LightControl not declared".

I now tried this:

ILightControl^ilc = dynamic_cast<ilightcontrol^>(obj);
ilc->Settings();

The cast works fine, but when I call the method I get the error:
"Object reference not set to an instance of an object."

I think the problem is, that I'm trying to create an Object of an interface. That is probably not possible.
But as I already have the right object, there must be a possibility to tell the compiler, that the object implements the interface ILightControl, and can therefore call the method Settings().

As LightControl is only defined in the dll, the software doesn't know LightControl at compilation time.

I defined the interface ILightControl in the dll and derived LightControl. I also defined ILightControl in my main program. Now I have to tell the compiler, that the object I created has the function Settings, and call it. This is the first time I'm working with interfaces, so I might overlook something.