2 Developing Custom Controls

The use of custom controls enables the AUI runtime functionality to be extended, and also allows the AUI runtime to interact with external applications. Custom controls supported by the AUI runtime are those ActiveX controls that are generally defined for Windows. A custom control is produced as a Dynamic Link Library (DLL). The AUI runtime accesses a custom control through interprocess communication (indirect call via VTABLE). The communication methods (interfaces) between the custom control and host are generically defined for ActiveX controls. This makes it possible to create custom controls as generic components that are not dedicated to AUITK but which are also accessible to other application processes. Creating well-designed custom controls is the key to developing a flexible and reusable system.

For general and detailed information on ActiveX controls, go to MSDN or refer to the published documentation.

This chapter discusses a special method of using custom controls for AUITK.