VB.NET Language in a Nutshell, Second Edition

Chapter 5. The .NET Framework: General Concepts

In this chapter, we discuss some of the main concepts in the .NET Framework. This is intended as a general overview, just to give you the “lay of the .NET land,” so to speak. For more information, see Thuan Thai and Hoang Q. Lam’s .NET Framework Essentials (O’Reilly, 2001).

Namespaces

The notion of a namespace plays a fundamental role in the .NET Framework. In general, a namespace is a logical grouping of types for the purpose of identification. For example, imagine that in a certain business there is an executive named John Smith, a secretary named John Smith, and a custodian named John Smith.

In this case, the name John Smith is ambiguous. When the paymaster stands on a table and calls out the names of people to receive their pay checks, the executive John Smith won’t be happy if he rushes to the table when the paymaster calls out his name and the envelope contains the custodian John Smith’s pay check.

To resolve the naming ambiguity, the business can simply define three namespaces: Executive, Secretarial, and Custodial. Now the three individuals can be unambiguously referred to by their fully qualified names:

• Executive.John Smith

• Secretarial.John Smith

• Custodial.John Smith

The .NET Framework Class Library (FCL), which we look at in more detail in Chapter 6, consists of several thousand classes and other types (such as interfaces, structures, and enumerations) that are divided into over 90 namespaces. These namespaces provide basic ...