The Microsoft Component Object Model (COM) is the foundation behind Visual Basic 6
, even if Visual Basic (VB) hides most of the inner details. To write better VB programs for the enterprise, chances are you'll need to take on at least some of the intricacies of COM. VB COM: A Visual Basic Programmer's Introduction to COM
provides an approachable guide to today's COM and other Microsoft technologies.
The book begins with one of the most approachable and effective tours of COM you're likely to find anywhere. The author covers COM components along with fundamental terms (such as interfaces, Globally Unique Identifiers (GUIDs), IUnknown and the registry) with a minimum of hassle. In a section on OLE Automation, the author shows how to use VB to script Excel spreadsheets, while explaining the details of early and late binding, IDispatch, and dual interfaces.
Next the author discusses how to build components, starting with ActiveX servers (both dynamic-link libraries [DLLs] and standalone EXEs) and proceeding to ActiveX controls. (The section on building controls is particularly strong, with good coverage of Ambient and Extender objects and connection points for event handling.) Throughout, VB COM relies on tools-based examples, with plenty of screen shots from VB 6 tools (such as its Class Builder Wizard). Later the book moves on to the enterprise with coverage of Distributed COM (DCOM), multi-tiered architectures, Microsoft Transaction Server (MTS) and emerging standards such as COM+.
In all, VB COM delivers a clear picture of the inner workings of COM for the VB developer with a useful mix of simplicity and essential technical detail. --Richard Dragan
This book is geared towards the Visual Basic programmer who wants to begin discovering the benefits of Microsoft's Component Object Model (called COM) and how to use COM to build more dynamic applications. COM has traditionally been considered as something that VB programmers don't need to think about too much: VB is supposed to look after all the nitty-gritty of COM, leaving the VB programmer to rapidly develop working business solutions. However, with Microsoft pushing hard on its multi-tiered technologies, more and more people are becoming aware that COM is something important. For any moderately advanced VB programming at all, COM is present - often under the guise of ActiveX. COM underlies most of what is going on in VB. COM is components and objects: and there are hundreds of objects and components even in the basic VB environment. So what's going on? What is COM? Why is it important? What can VB programmers do with COM? For newcomers to COM, this is all a bit mysterious. For competent but relatively non-technical VB professional programmers, the full story of COM is still somewhat disjointed.