Components of an ActiveX Designer

At a minimum, every ActiveX designer must support the following:

A visual designer to handle the user interface at design time.
ActiveX and COM interfaces for support for type information, programmability, and a class factory.
Registration in the system-wide registry, so that applications and development tools can find the ActiveX designer.

The following figure summarizes these minimum requirements.

In addition, an ActiveX designer may create a separate object that is used at run time.

ActiveX designers are usually distributed in dynamic-link libraries (.dll). However, if the ActiveX designer is also an ActiveX control, it can be distributed in an .ocx file instead.