What is the difference between AxInterop and Interop?

Question

I\'ve added an .ocx to the toolbox in VS. Two .dll\'s were created: Interop.NNN.dll, AxInterop.NNN.dll.

What is each one? Are they both required?

Answer 1

Interop.xxx.dll and AxInterop.xxx.dll are runtime callable wrappers (RCW) for a referenced COM and an ActiveX dll respectively.

interop.xxx.dll is purely an automation (a COM dll) wrapper, enabling you to manipulate the object within the namespace of your application. AxInterop.xxx.dll is a control wrapper for a ActiveX control, which can be dragged onto the form.