Visual Studio defines thousands of variables, classes, routines, and other entities to provide tools for your applications. It categorizes them in namespaces to prevent name collisions and to make it easier for you to find the items you need.

The .NET Framework root namespaces are named Microsoft and System. The Microsoft namespace includes namespaces that support different programming languages and tools. For example, typical namespaces include CSharp, JScript, and VisualBasic, which contain types and other tools that support the C#, JScript, and Visual Basic languages. The Microsoft namespace also includes the Win32 namespace, which provides classes that handle operating system events and that manipulate the registry.

The System namespace contains a huge number of useful programming items, including many nested namespaces. For example, the System.Drawing namespace contains classes related to drawing, System.Data contains classes related to databases, System.Threading holds classes dealing with multithreading, and System.Security includes classes for working with security and cryptography.

Note that these namespaces are not necessarily available to your program at all times. For example, by default, the Microsoft.JScript namespace is not available to Visual Basic programs. To use it, you must first add a reference to the Microsoft.JScript.dll library.

Visual Studio includes so many programming tools that the namespace hierarchy is truly enormous. Namespaces ...

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