In this chapter:
Almost everything on the Windows platform is built on top of COM. The technology is ubiquitous. In this chapter, we will take ourselves into the realm of COM and its coexistence with the Web. In order to successfully build and run the examples in this chapter, you should have the following software and environment:
OCRServer component, developed in Chapter 6, must be installed and registered on a server machine.
Microsoft Peer Web Server 3.0, or greater, must be installed, and the WWW service must be running. You can verify this using the Microsoft Internet Service Manager (inetmgr.exe) utility.
You must have Microsoft Internet Explorer (IE) 3.0.2, or greater.
You must have the
Wang Image Edit ActiveX Control, which is shipped with Windows NT 4.0 or greater.
Assuming that we have the preliminary requirements in place, we will develop a few ActiveX controls in this chapter. An ActiveX control is simply a COM object, because the only requirement for an object to be called an ActiveX control is that it implements the IUnknown interface. ActiveX controls live inside an in-process component (DLL or OCX) that can be dynamically loaded by an out-of-process component. This out-of-process server, which can be any EXE that implements the necessary interfaces, is specifically called an ActiveX container or simply a container. A perfect example of a container ...