具体描述
The Visual Basic programming environment is designed to hide as many low-level system details as possible. While this approach can speed development time by allowing the developer to focus on the task at hand, it actually hinders the process when it obscures details the developer needs to understand or control. Such is often the case for programmers who are developing components that take advantage of COM+ services. "COM+ Programming with Visual Basic" addresses the information needs of these developers. For instance, despite the marketing hype about COM+ as the new and improved version of COM, classic COM is very much the foundation on which COM+ is built: COM+ components are a particular kind of COM component. Visual Basic hides almost all COM implementation details; yet it is precisely in the area of COM+ programming that these hidden details are most important. Therefore, the text devotes significant content to exploring COM internals: interface-based programming; how COM interfaces work internally; how COM components are activated; and how versioning COM components works in Visual Basic. The second section focuses on incorporating individual COM+ services, like transaction support, security, and asynchronous operations, into applications. The author concludes by discussing what developers need to learn to transition to Microsoft's coming .NET framework. Regardless of what lies ahead for .NET, many distributed systems are being built today with COM+. COM+ Programming with Visual Basic focuses on topics relevant to distributed applications that are here to stay: how to use interfaces; passing objects by reference or by value; what it means to have multithreaded applications; how declarative programming works; how to program within a distributed transaction; and how to add role-based security to applications.
