VB.NET Core Classes in a Nutshell

Working with the .NET FCL

Despite its vast size, the .NET FCL is a manageable collection of classes and their methods. This is because, unlike more traditional development tools such as the Win32 API, the .NET FCL is a collection of types (classes, interfaces, delegates, events, structures, modules, and enumerations) and their members organized into namespaces. A namespace is simply a logical grouping of classes that can in turn contain other namespaces, so that a collection of namespaces forms an inverse hierarchical tree. Organization of types into namespaces helps to prevent collisions in the event that types are identically named.

Although the .NET system of namespaces does not have a single root, we can consider the System namespace at the top of the .NET FCL hierarchy. It includes a wide variety of basic system classes, including data types, exception types, and types defining the most important attributes.

Defining Accessible Namespaces

The types in a namespace, in turn, reside in an assembly, which is simply a logical unit of deployment. An assembly provides the Microsoft Intermediate Language (MSIL) code for its contents, which is packaged in a Windows portable executable (PE) file. An assembly also specifies security permissions for itself, maintains a list of the types that it defines and their scopes, and specifies rules for resolving references to external types.

The assemblies in which namespaces of the .NET FCL reside are Windows dynamic link libraries (.DLLs). Typically, ...