COM+ Programming with Visual Basic

Chapter 7. COM+ Applications

Chapter 1 through Chapter 6 focused on what is typically known as the core COM architecture. It gave you an inside view of what interfaces look like in memory as well as how in-process servers are activated and deployed and how out-of-process servers differ. Chapter 7 through Chapter 10 are all about the COM+ architecture and services. In this chapter we move beyond the core COM architecture and begin exploring what COM+ is.

The COM+ principle is based on the following idea: let Microsoft do it for you. If you think about the success of Visual Basic, a lot of it can be attributed to the vast number of third-party controls. Third-party controls offer a lot of features and enhancements that can be instantly added to your application to create rich user interfaces. With controls, another group of developers creates and maintains the functionality. Imagine how long it would take you to create an application if you had to create your own grid control or your own 3-D charting tool.

Along the same lines, a number of features that would be too difficult to implement by hand are necessary in distributed business applications. These features include group-based (or role-based) security, distributed transactioning, component load balancing, automatic data replication, the creation of client setup programs, synchronization, thread pooling, sharing of resources, and so on. All of these features or services are too time consuming to add by hand, yet they are a critical ...