Organizing Types Within Namespaces

Namespaces are defined within Namespace..End Namespace blocks. Every namespace can expose the following types and members:

• Classes

• Structures

• Enumerations

• Modules

• Interfaces

• Delegates

• Nested namespaces

Listing 9.1 shows an example of a namespaces exposing most of the preceding listed members.

Listing 9.1 Organizing Types Within a Namespace

As you can see from Listing 9.1, you can organize your custom objects within a namespace. The code implements an abstract class Person, three derived classes (Contact, Employee, and Customer), an interface (which is then implemented by the Contact class), an enumeration (PersonType), a structure (PersonInformation), and a module (GlobalDeclarations). The namespace becomes part of the full name of a type. For example, the full name for the Contact class is People.Contact. Therefore, if you need to access a type defined within a namespace, you need to refer to it writing the full name, as in the following line of code:

Dim firstContact As New People.Contact

Namespaces can also expose partial classes. This is a common situation within .NET Framework built-in namespaces.