•  Diff: between ActiveX Controls & ActiveX DLL

An ActiveX control is a COM-based object that can draw itself in its own window, respond to events (such as mouse clicks), and be managed through an interface that includes properties and methods similar to those in Automation objects. The only limitation on the kinds of ActiveX controls you can create is your imagination.

Components provide reusable code in the form of objects. An application that uses a component's code, by creating objects and calling their properties and methods, is referred to as a client . Components can run either in-process or out-of-process with respect to the clients that use their objects. An in-process component, or ActiveX DLL, runs in another application's process. The client may be the application itself, or another in-process component that the application is using.