Professional Visual Basic® 2010 and .NET 4

Chapter 2. Objects and Visual Basic

WHAT YOU WILL LEARN IN THIS CHAPTER

• Object Oriented Terminology

• Composition of an Object

• Characteristics of Value Types versus Reference Types

• Primitive Types

• Commands: If Then, Else, Select Case

• Common Value Types (Structures)

• Common Reference Types (Classes)

• XML literals

• Parameter passing ByVal and ByRef

• Variable scope

• Working with Objects

• Understanding Binding

• Data type conversions

• Creating Classes

• Event Handling

• Advanced Object Oriented Programming

• Using Lambdas

Visual Basic supports the four major defining concepts required for a language to be fully object-oriented:

• Abstraction — Abstraction is merely the ability of a language to create "black box" code, to take a concept and create an abstract representation of that concept within a program. A Customer object, for instance, is an abstract representation of a real-world customer. A DataTable object is an abstract representation of a set of data.

• Encapsulation — Encapsulation is the concept of a separation between interface and implementation. The idea is that you can create an interface (public methods, properties, fields, and events in a class), and, as long as that interface remains consistent, the application can interact with your objects. This remains true even when you entirely rewrite the code within a given method — thus, the interface is independent of the implementation. The publicly exposed interface becomes what is known as a contract. It is this contract that you will look to limit changes to for ...