What is an ActiveX control ?

What is ActiveX ?

ActiveX is an open integration platform that enables software components to interact with one another. The technology is developed by Microsoft based on the Component Object Model (COM). The purpose of the technology is to provide an open, object-oriented technology which allows developers to both develop and integrate software components that are developed according to the ActiveX standard, the ActiveX controls.

An ActiveX control is a component implementing a specific functionality that can be reused in several different programs.
The ActiveX control contains all the logic needed to do its job, graphical display capabilities, mouse and keyboard handling, etc. It cannot live on its own, it has to live in a container that will provide a framework like a portion of a window to show its output, menus, etc.

IGSS is such a container. It allows you to insert ActiveX controls and bind them to dynamic IGSS values and, of course, also change their static properties. Click here for further information about IGSS and ActiveX controls.

The interface to an ActiveX control

To make the integration of the control and the container easier, the control provides a number of standardised interfaces, as follows:

Properties: Attributes that control the behaviour of the control, like the use of fonts, colors, etc.
Some static properties can be defined in Definition only, while others can be used to send data into the control during supervision, for example, values that are bound to an IGSS object.

Methods: Functions made available by the control, so the container can ask the control to perform different tasks.

Events: The control can notify the container when certain events occur, for example, when the user operates the control, an IGSS object will get changed.

ActiveX documentation

In most cases, the documentation of an ActiveX control will be available as online Help. In that case, you will have direct access to that Help file from IGSS. This is done to allow you to stay in IGSS while you change the properties of the ActiveX control. The Help file can be accessed by right-clicking one of the ActiveX control properties and selecting OCX Help Index.

The lion’s share of using an ActiveX control lies in understanding the individual properties that you can set which means that access to its documentation is crucial. IGSS merely provides an interface to the ActiveX control and, therefore, does not “know” the properties of the control. It is recommended to investigate the quality of the documentation, if possible, before actually buying an ActiveX control.