In this tutorial we will be creating
MathComp which is a DLL or Inproc server and exposes the Add and Sub functions.
An MFC Dialog Based Application which acts like a Client for MathComp
For complete tutorial refer Tutorial
Definition: ActiveX controls are COM components which are self-registering and Implements standard interfaces that deal specifically with GUI-based tasks such as rendering, sizing, activation, and property persistence.
An ActiveX control is anything you might see in the Toolbox of Visual studio (i.e. EditBox, combobox e.t.c) we can even use the Activex controls in web pages using and handling events with Javascript.
For complete tutorial Refer ActiveX Control Tutorial