Chapter 04 : Selected Visual Basic .NET Advanced Topics

Overview

Chapter 3 introduced selected core Microsoft Visual Basic .NET programming issues. Most of those issues are traditional ones that have a strong relationship with similar topics in classic Visual Basic. This chapter considers four additional Visual Basic .NET topics. However, these features of the programming environment are either brand new or substantially changed from Visual Basic s previous incarnation. My goal in this chapter is to arouse your curiosity about the new programming topics and to present code samples that will empower you to exploit the new techniques as you create your own custom solutions.

My objective for Chapter 3 and this chapter is to convey a good working knowledge of many core Visual Basic .NET programming topics that target the skill sets that Microsoft Access developers will likely find useful. In several cases, I explicitly use Microsoft Access databases to make it easy for you to see the relevance of these techniques to your particular kind of programming tasks . In other cases, I present the core topics without a database reference to present the programming concept cleanly and simply.

The four areas covered in this chapter are file processing, event processing, class inheritance, and a new style of run-time error processing. The System.IO namespace introduces a set of new classes for manipulating files. In particular, you will learn about the StreamWriter and StreamReader objects for processing text files, but you will also learn how to programmatically manipulate binary files such as the image files associated with the Northwind database. Furthermore, you will learn about new ways of handling events and will see samples demonstrating the raising of events from classes that expose Access database objects. In addition, you will learn how to work with inheritance, a powerful concept that facilitates code reuse by letting one class inherit members , such as properties and methods , from another. Again, you will see inheritance in action with Access database objects. The chapter closes with a discussion of structured exception handling (SEH) ”a new and improved means of processing run-time errors. I ll explain why SEH is superior to the unstructured run-time error processing in classic Visual Basic. As with most of the topics covered throughout the book, the SEH focus is on the presentation of code samples that will empower you.