.NET Framework

The .NET Framework class library is a set of namespaces, classes, interfaces, and value types that are used in our .NET applications, components, and controls. Contrary to class libraries such as Microsoft Foundation Classes (MFC) or Borland Visual Class Library (VCL), the .NET Framework class library is language-independent. This means it can be used from any programming language, such as Visual Basic.NET, C#.NET, C++ with managed extensions, J#.NET, or any third-party language that conforms to the Common Language Specification (CLS).

The .NET Framework class library includes classes that support the following functions:

base and user-defined data types;

support for handling exceptions;

input/output and stream operations;

communications with the underlying system;

access to data;

ability to create Windows–based GUI applications;

ability to create web–client and server applications;

support for creating web services.

All classes implemented in the .NET class library are organized into namespaces. Each namespace contains classes and other types that are related to the specific task or set of tasks – input/output operations, web applications creation, working with data and XML, and so on. The main namespaces in the .NET class library.
 
System
 Contains fundamental classes and base classes that define common value and reference data types, events and event handlers, interfaces, processing exceptions, data conversion, mathematics, as well as garbage collection and application environment management. Some of the classes defined in the namespace are covered in this chapter and also in Chapters 4 and 5.
 
System.IO
 Provides classes that support asynchronous and synchronous reading from and writing to data streams and files. Contains classes like FileStream, MemoryStream, Path, and Directory. We will learn about this namespace and its classes in the next chapter.
 
System.Collections
 Contains interfaces and classes that define various collections of objects, such as lists, arrays, hash tables, stacks, queues, and dictionaries. The classes defined in this namespace are covered in this chapter.
 
System.Threading
 Provides classes and interfaces that support multithreaded programming. Contains classes such as Thread, ThreadPool, Mutex, and AutoResetEvent.
 
System.Reflection
 Contains classes that provide dynamic binding and a managed view of loaded types, methods, and fields. Contains classes such as Assembly, Module, and MethodInfo.
 
System.Security
 Implements a security system, including base classes for permissions. Includes classes of the likes of SecurityManager, PermissionSet, and CodeAccessPermission.
 
System.Net
 Provides support for network programming. Includes, for example, the classes HttpWebRequest, IPAddress, Dns, and Connection. We will learn about this namespace and its classes in the next chapter.
 
System.Data
 Contains classes that implement ADO.NET. Child namespaces include OLEDB, and SqlClient. This namespace will be discussed in Chapter 12.
 
System.XML
 The System.XML namespace provides support for processing XML documents. Child namespaces include Schema, XSL, and XPath. We will discuss this namespace and its secondary namespaces in Chapter 14.
 
System.Web
 Serves as a base for ASP.NET applications. Contains such classes as HTTPRequest, HTTPResponse, and HTTPServerUtility. Child namespaces include Caching, Configuration, Security, and UI. We will discuss this namespace and its secondary namespaces in Chapters 6 and 7.
 
System.Web.Services
 Enables us to build and use web services. Secondary namespaces include Description, Discovery, and Protocols. We will discuss this namespace and its secondary namespaces in Chapter 15.
 
System.Windows.Forms
 Contains classes used to create form-based Windows applications. We will discuss this namespace in Chapters 8, 9, and 10
 
System.Drawing
 Provides access to the graphics functionality of GDI+. Contains secondary namespaces such as Design, Drawing2D, Imaging, Printing, and Text. We will discuss this namespace and its secondary namespaces in Chapter 11.
 
System.Globalization System.Resources
 Contains classes that define culture-related information – language, country/region, calendar, and so on. Classes from the Resources namespace are used to create localized Windows and web applications.