Using an ActiveX object as a FORMS extension

Using an ActiveX object as a FORMS extension (plug-in application) is one of four ways of developing event handlers. It can be convenient to use an ActiveX object to handle all the FORMS events. You get the advantages of third-party tools such as Microsoft Visual Basic or Borland’s Delphi, which offer features like advanced window and dialog handling, database support, advanced programming language capabilities, and debugging in a truly integrated development environment.

This method has advantages over using the object as an event server:

• Functionality is similar to regular customization module, but far more flexible.

• It allows multiple plug-ins (program extensions) to be active at the same time. The event server mechanism does not support this.

• Each plug-in subscribes to a specified set of events, so performance is faster than with the event server mechanism.

Other features

• Most extensions are COM objects, but not all of them. Plug-in types and APIs:

• COM IDispatch

• DLL interface for maximum performance

• Extensions that are COM objects are implemented in DLLs or executable files

• Develop the object in any language that supports COM, for example VB or C++

To use an ActiveX object as a FORMS extension, you must:

1. Program an ActiveX object. (How?)

2. Register the object in Windows.

3. Register it as a FORMS extension.

Related topic

Calling conventions (read this if two or more extensions subscribe to the same event)