Introduction

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Large-scale enterprise applications have special requirements. They need to be secure, reliable, available, efficient, and scalable. Of course, programmers can write tons of code to implement these features, but the problem is that they need to do the same for every enterprise application that they develop. Reinventing the wheel is undesirable. Nevertheless, that's how programmers traditionally developed enterprise applications on the Windows platform.

This paradigm changed when Microsoft introduced technologies such as Microsoft Transaction Server (MTS) and its improved successor COM+. COM+ incorporates functionality for security, reliability, availability, efficiency, and scalability as part of the operating system infrastructure. As a result, programmers need not write these features repeatedly in each application that they develop. Instead, they can just request the operating system to provide these services to the applications.

This chapter focuses on how to use various COM+ services from your .NET Framework applications. The chapter opens by discussing the evolution of component services so that you can appreciate how and why this platform has evolved.

COM+ understands the Component Object Model (COM) but does not understand .NET. However, the .NET Framework provides features by which you can expose a .NET component as a COM component. That's what you will discover next : how to expose a .NET component to COM or COM+.

In the next part of the chapter, you will discover the architecture of component services. You will also learn about the declarative programming model and how COM+ uses context and interception to provide its services.

In the next section, you'll learn how to create a .NET component and how to deploy, register, and configure it to use the COM+ services.

Finally, you'll discover a set of COM+ services including object construction, object pooling, just-in-time activation, automatic transaction management, and queued components . You will gain insight on how each of these services work: Systematic tutorials are provided to illustrate how to use these services in your own applications.

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