Introduction

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Understanding COM takes time and energy. I can say with great confidence that there is always more to learn. However, as with most technologies, COM does provide a core body of knowledge that works as the backbone for just about everything else. For example, once you understand the building blocks of interfaces, coclasses, class factories, and COM binaries, the foundation is laid for numerous related aspects of COM, such as the ActiveX control, distributed COM, and connectable objects (just to name a few).

The relationship between COM and the numerous ActiveX technologies out there can be equated to an understanding of mathematics and the various applied sciences. If you don't understand how to work with basic algebraic equations, you can forget taking classes in physics, chemistry, and biology. The same holds true here: Without an understanding of the algebra of COM, forget the science of ActiveX. Moreover, without an understanding of COM, forget ATL.

Once an individual has come to understand the core building blocks of the COM architecture, the next logical step is to adopt a component framework to help lessen the burden of repetitive code. ATL is the C++ developer's COM framework of choice. With ATL by your side, you can successfully spend less time handing out interface pointers and more time concentrating on the domain-specific coding task at hand. However, an ATL developer who does not understand the architecture of COM is no better off than an MFC developer who has no understanding of the central Win32 APIs. This book offers a firm foundation in COM, as well as the ATL framework.

What You Need to Use This Book

Learning COM and ATL are not passive activities. A developer does not come to understand these complex systems because his current job demands it, because she owns a book on the topic, or because he or she flipped through the latest issue of Microsoft Systems Journal! You must dig in and make it happen. The philosophy of this book is that you gain an understanding of COM and ATL by writing code yourself. Lots of it.

To this end, every chapter in this book has a number of integrated lab assignments that give you numerous opportunities to build COM clients and servers both in raw C++ as well as ATL. To get the most out of this book (and the labs), you should have the following workstation configuration:

  • A full installation of Visual C++ 6.0 (which gives you a full installation of ATL).

  • A full installation of Visual Basic 6.0 (as we will build a number of VB test clients).

  • If you are interested in Java/COM integration, a full installation of Visual J++ 6.0.

  • A full installation of Visual Studio's online help (MSDN).

  • Microsoft Internet Explorer 5 to test the various web-based clients.

As well, if you are interested in working though the distributed COM (DCOM) lab assignment, you will (of course) need two networked computers, ideally each running Windows NT to allow for the full range of DCOM options.

The source code (and screen shots) used in this book were built and tested on both Windows NT4 (SP5) and Win98 Second Edition. The source code was compiled using the Microsoft Visual Studio suite of tools, SP3.



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Developer's Workshop to COM and ATL 3.0
Developers Workshop to COM and ATL 3.0
ISBN: 1556227043
EAN: 2147483647
Year: 2000
Pages: 171

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