Base Class Library
Encyclopedia
The Base Class Library is a standard library
available to all languages using the .NET Framework
. .NET includes the BCL in order to encapsulate a large number of common functions, such as file reading and writing, graphic rendering, database
interaction, and XML
document manipulation, which makes the programmer's job easier. It is much larger in scope than standard libraries for most other languages, including C++
, and is comparable in scope to the standard libraries of Java
. The BCL is sometimes incorrectly referred to as the Framework Class Library
(FCL), which is a superset including the Microsoft.* namespaces.
The BCL is updated with each version of the .NET Framework.
, but all are included as part of the libraries that are provided with Microsoft's implementation of the .NET Framework.
335 and ISO/IEC
23271:2006 standards.
System : This namespace
includes the core needs for programming. It includes base types like String
, DateTime, Boolean
, and so forth, support for environments such as the console, math functions, and base classes for attributes, exceptions, and arrays.
System.Collections : Defines many common containers
or collections used in programming, such as lists, queues, stack
s, hashtables
, and dictionaries. It includes support for generics
.
System.Diagnostics : Provides the ability to diagnose applications. It includes event logging, performance counters, tracing, and interaction with system processes.
System.Globalization : Provides help for writing internationalized applications. "Culture-related information, including the language, the country/region, the calendars in use, [and] the format patterns for dates, currency, and numbers" can be defined.
System.IO : Enables reading from and writing to different streams, such as files or other data streams. Also provides a connection to the file system
.
System.Net : Provides an interface "for many of the protocols used on networks today", such as HTTP, FTP, and SMTP. Secure communication is supported by protocols such as SSL.
System.Reflection : Provides an object view of types, methods, and fields; and "the ability to dynamically create and invoke types". It exposes the API to access the Reflective programming
capabilities of CLR.
System.Runtime : Allows management of the runtime behavior of an application or the CLR
. Some of the included abilities are interoperable with COM
or other native code, writing distributed applications
, and serializing
objects into binary
or SOAP
.
System.Security : "Provides the underlying structure of the common language runtime security system." This namespace allows security to be built into applications based on policy and permissions. It provides services such as cryptography
.
System.Text : Supports various encodings, regular expressions, and a more efficient mechanism for manipulating strings (StringBuilder).
System.Threading : Helps facilitate multithreaded programming. It allows the synchronizing of "thread activities and access to data" and provides "a pool of system-supplied threads."
System.Xml
: "Provides standards-based support for processing XML
," including reading, writing, schemas, serialization, searching, and transforming.
and/or ISO
standards, and are specific to Microsoft implementation. However, even if implementing them is not mandatory, some of them may have been implemented completely or partially by other .NET implementations.
System.CodeDom : This library provides the ability to create code and run it, at runtime.
System.ComponentModel : Provides the ability to implement the run-time and design-time behavior of components and controls. It contains the infrastructure "for implementing attributes and type converters, binding to data sources, and licensing components."
System.Configuration : Provides the infrastructure for handling configuration data.
System.Data : This namespace represents the ADO.NET
architecture, which is a set of computer software components that can be used by programmers to access data and data services.
System.Deployment : Allows customization of the way applications upgrade when using ClickOnce
.
System.DirectoryServices : Provides easy access to Active Directory
from managed code.
System.Drawing : Provides access to GDI+
graphics functionality, including support for 2D and vector graphics, imaging, printing, and text services.
System.EnterpriseServices : "Provides .NET objects with access to COM+ services making the .NET Framework objects more practical for enterprise applications."
System.Linq
: Defines the
providers to be plugged in.
System.Linq.Expressions: Allows Delegates
and Lambda expression
s to be represented as expression trees, so that the high-level code can be examined and processed at runtime.
System.Management : Allows querying for system information, "such as how much free space is left on the disk, what is the current CPU utilization, which database a certain application is connected to, and much more."
System.Media : Provides the ability to play system sounds and .wav files.
System.Messaging : Provides the ability "to connect to, monitor, and administer message queues on the network and send, receive, or peek messages." .NET Remoting
is another name for some of the functionality provided. This namespace is being superseded by Windows Communication Foundation
.
System.Resources : Allows management of resources in the application in order to internationalize an application for different cultures and languages.
System.ServiceProcess : Allows the creation of applications that run as a service within Windows
.
System.Timers : "Allows you to raise an event on a specified interval."
System.Transactions : Provides support for local or distributed transactions.
System.Web : Provides various web related functionality. It enables browser-server communication and the creating XML Web service
s. Most or all of these libraries are referred to as the ASP.NET
architecture.
System.Windows.Forms : This namespace contains the Windows Forms
architecture which provides access to the native Windows
interface elements by wrapping the existing Windows API
. This allows for writing graphical applications for Windows from within managed code. This system is being superseded by the Windows Presentation Foundation
.
Standard library
A standard library for a programming language is the library that is conventionally made available in every implementation of that language. In some cases, the library is described directly in the programming language specification; in other cases, the contents of the standard library are...
available to all languages using the .NET Framework
.NET Framework
The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...
. .NET includes the BCL in order to encapsulate a large number of common functions, such as file reading and writing, graphic rendering, database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
interaction, and XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
document manipulation, which makes the programmer's job easier. It is much larger in scope than standard libraries for most other languages, including C++
C++
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
, and is comparable in scope to the standard libraries of Java
Java Class Library
The Java Class Library is a set of dynamically loadable libraries that Java applications can call at run time. Because the Java Platform is not dependent on any specific operating system, applications cannot rely on any of the existing libraries...
. The BCL is sometimes incorrectly referred to as the Framework Class Library
Framework Class Library
The Framework Class Library is a standard library and one of two core components of Microsoft .NET Framework. The FCL is a collection of thousands of reusable classes , interfaces and value types...
(FCL), which is a superset including the Microsoft.* namespaces.
The BCL is updated with each version of the .NET Framework.
Namespaces
Some of the namespaces may or may not be officially considered part of the BCL by MicrosoftMicrosoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
, but all are included as part of the libraries that are provided with Microsoft's implementation of the .NET Framework.
Standardized namespaces
These are the namespaces that are standardized as of the ECMAEcma International
Ecma International is an international, private non-profit standards organization for information and communication systems. It acquired its name in 1994, when the European Computer Manufacturers Association changed its name to reflect the organization's global reach and activities...
335 and ISO/IEC
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
23271:2006 standards.
System : This namespace
Namespace (computer science)
A namespace is an abstract container or environment created to hold a logical grouping of unique identifiers or symbols . An identifier defined in a namespace is associated only with that namespace. The same identifier can be independently defined in multiple namespaces...
includes the core needs for programming. It includes base types like String
String (computer science)
In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet....
, DateTime, Boolean
Boolean datatype
In computer science, the Boolean or logical data type is a data type, having two values , intended to represent the truth values of logic and Boolean algebra...
, and so forth, support for environments such as the console, math functions, and base classes for attributes, exceptions, and arrays.
System.Collections : Defines many common containers
Container (data structure)
In computer science, a container is a class, a data structure, or an abstract data type whose instances are collections of other objects. In other words; they are used for storing objects in an organized way following specific access rules...
or collections used in programming, such as lists, queues, stack
Stack
-Mathematics:* Stack , general category-theoretical concept to formalise "pull-back" operations in geometry and algebra* Algebraic stack, a generalisation of scheme and algebraic space in algebraic geometry; a specific type of the above-Computers:...
s, hashtables
Hash table
In computer science, a hash table or hash map is a data structure that uses a hash function to map identifying values, known as keys , to their associated values . Thus, a hash table implements an associative array...
, and dictionaries. It includes support for generics
Generic programming
In a broad definition, generic programming is a style of computer programming in which algorithms are written in terms of to-be-specified-later types that are then instantiated when needed for specific types provided as parameters...
.
System.Diagnostics : Provides the ability to diagnose applications. It includes event logging, performance counters, tracing, and interaction with system processes.
System.Globalization : Provides help for writing internationalized applications. "Culture-related information, including the language, the country/region, the calendars in use, [and] the format patterns for dates, currency, and numbers" can be defined.
System.IO : Enables reading from and writing to different streams, such as files or other data streams. Also provides a connection to the file system
File system
A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...
.
System.Net : Provides an interface "for many of the protocols used on networks today", such as HTTP, FTP, and SMTP. Secure communication is supported by protocols such as SSL.
System.Reflection : Provides an object view of types, methods, and fields; and "the ability to dynamically create and invoke types". It exposes the API to access the Reflective programming
Reflection (computer science)
In computer science, reflection is the process by which a computer program can observe and modify its own structure and behavior at runtime....
capabilities of CLR.
System.Runtime : Allows management of the runtime behavior of an application or the CLR
Common Language Runtime
The Common Language Runtime is the virtual machine component of Microsoft's .NET framework and is responsible for managing the execution of .NET programs. In a process known as just-in-time compilation, the CLR compiles the intermediate language code known as CIL into the machine instructions...
. Some of the included abilities are interoperable with COM
Component Object Model
Component Object Model is a binary-interface standard for software componentry introduced by Microsoft in 1993. It is used to enable interprocess communication and dynamic object creation in a large range of programming languages...
or other native code, writing distributed applications
Distributed computing
Distributed computing is a field of computer science that studies distributed systems. A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal...
, and serializing
Serialization
In computer science, in the context of data storage and transmission, serialization is the process of converting a data structure or object state into a format that can be stored and "resurrected" later in the same or another computer environment...
objects into binary
Binary file
A binary file is a computer file which may contain any type of data, encoded in binary form for computer storage and processing purposes; for example, computer document files containing formatted text...
or SOAP
SOAP
SOAP, originally defined as Simple Object Access Protocol, is a protocol specification for exchanging structured information in the implementation of Web Services in computer networks...
.
System.Security : "Provides the underlying structure of the common language runtime security system." This namespace allows security to be built into applications based on policy and permissions. It provides services such as cryptography
Cryptography
Cryptography is the practice and study of techniques for secure communication in the presence of third parties...
.
System.Text : Supports various encodings, regular expressions, and a more efficient mechanism for manipulating strings (StringBuilder).
System.Threading : Helps facilitate multithreaded programming. It allows the synchronizing of "thread activities and access to data" and provides "a pool of system-supplied threads."
System.Xml
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
: "Provides standards-based support for processing XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
," including reading, writing, schemas, serialization, searching, and transforming.
Non-standardized namespaces
These are the namespaces that are not standardized as of the ECMAEcma International
Ecma International is an international, private non-profit standards organization for information and communication systems. It acquired its name in 1994, when the European Computer Manufacturers Association changed its name to reflect the organization's global reach and activities...
and/or ISO
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
standards, and are specific to Microsoft implementation. However, even if implementing them is not mandatory, some of them may have been implemented completely or partially by other .NET implementations.
System.CodeDom : This library provides the ability to create code and run it, at runtime.
System.ComponentModel : Provides the ability to implement the run-time and design-time behavior of components and controls. It contains the infrastructure "for implementing attributes and type converters, binding to data sources, and licensing components."
System.Configuration : Provides the infrastructure for handling configuration data.
System.Data : This namespace represents the ADO.NET
ADO.NET
ADO.NET is a set of computer software components that programmers can use to access data and data services. It is a part of the base class library that is included with the Microsoft .NET Framework. It is commonly used by programmers to access and modify data stored in relational database systems,...
architecture, which is a set of computer software components that can be used by programmers to access data and data services.
System.Deployment : Allows customization of the way applications upgrade when using ClickOnce
ClickOnce
ClickOnce is a Microsoft technology that enables the user to install and run a Windows application by clicking a link in a web page. ClickOnce is a component of Microsoft .NET Framework 2.0 and later, supports deploying applications made with Windows Forms or Windows Presentation Foundation...
.
System.DirectoryServices : Provides easy access to Active Directory
Active Directory
Active Directory is a directory service created by Microsoft for Windows domain networks. It is included in most Windows Server operating systems. Server computers on which Active Directory is running are called domain controllers....
from managed code.
System.Drawing : Provides access to GDI+
Graphics Device Interface
The Graphics Device Interface is a Microsoft Windows application programming interface and core operating system component responsible for representing graphical objects and transmitting them to output devices such as monitors and printers....
graphics functionality, including support for 2D and vector graphics, imaging, printing, and text services.
System.EnterpriseServices : "Provides .NET objects with access to COM+ services making the .NET Framework objects more practical for enterprise applications."
System.Linq
Language Integrated Query
Language Integrated Query is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages, although ports exist for Java, PHP and JavaScript....
: Defines the
IQueryable interface and related methods, that lets LINQLanguage Integrated Query
Language Integrated Query is a Microsoft .NET Framework component that adds native data querying capabilities to .NET languages, although ports exist for Java, PHP and JavaScript....
providers to be plugged in.
System.Linq.Expressions: Allows Delegates
Delegate (.NET)
A delegate is a form of type-safe function pointer used by the .NET Framework. Delegates specify a method to call and optionally an object to call the method on. They are used, among other things, to implement callbacks and event listeners....
and Lambda expression
Lambda expression
Lambda expression may refer to:*Anonymous function*Lambda calculus#Definition...
s to be represented as expression trees, so that the high-level code can be examined and processed at runtime.
System.Management : Allows querying for system information, "such as how much free space is left on the disk, what is the current CPU utilization, which database a certain application is connected to, and much more."
System.Media : Provides the ability to play system sounds and .wav files.
System.Messaging : Provides the ability "to connect to, monitor, and administer message queues on the network and send, receive, or peek messages." .NET Remoting
.NET Remoting
.NET Remoting is a Microsoft application programming interface for interprocess communication released in 2002 with the 1.0 version of .NET Framework. It is one in a series of Microsoft technologies that began in 1990 with the first version of Object Linking and Embedding for 16-bit Windows...
is another name for some of the functionality provided. This namespace is being superseded by Windows Communication Foundation
Windows Communication Foundation
The Windows Communication Foundation , previously known as "Indigo", is an application programming interface in the .NET Framework for building connected, service-oriented applications.-The architectures:...
.
System.Resources : Allows management of resources in the application in order to internationalize an application for different cultures and languages.
System.ServiceProcess : Allows the creation of applications that run as a service within Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
.
System.Timers : "Allows you to raise an event on a specified interval."
System.Transactions : Provides support for local or distributed transactions.
System.Web : Provides various web related functionality. It enables browser-server communication and the creating XML Web service
Web service
A Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...
s. Most or all of these libraries are referred to as the ASP.NET
ASP.NET
ASP.NET is a Web application framework developed and marketed by Microsoft to allow programmers to build dynamic Web sites, Web applications and Web services. It was first released in January 2002 with version 1.0 of the .NET Framework, and is the successor to Microsoft's Active Server Pages ...
architecture.
System.Windows.Forms : This namespace contains the Windows Forms
Windows Forms
Windows Forms is the name given to the graphical application programming interface included as a part of Microsoft .NET Framework, providing access to native Microsoft Windows interface elements by wrapping the extant Windows API in managed code...
architecture which provides access to the native Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
interface elements by wrapping the existing Windows API
Windows API
The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces available in the Microsoft Windows operating systems. It was formerly called the Win32 API; however, the name "Windows API" more accurately reflects its roots in 16-bit Windows and its support on...
. This allows for writing graphical applications for Windows from within managed code. This system is being superseded by the Windows Presentation Foundation
Windows Presentation Foundation
Developed by Microsoft, the Windows Presentation Foundation is a computer-software graphical subsystem for rendering user interfaces in Windows-based applications. WPF, previously known as "Avalon", was initially released as part of .NET Framework 3.0. Rather than relying on the older GDI...
.
See also
- ADO.NETADO.NETADO.NET is a set of computer software components that programmers can use to access data and data services. It is a part of the base class library that is included with the Microsoft .NET Framework. It is commonly used by programmers to access and modify data stored in relational database systems,...
- ASP.NETASP.NETASP.NET is a Web application framework developed and marketed by Microsoft to allow programmers to build dynamic Web sites, Web applications and Web services. It was first released in January 2002 with version 1.0 of the .NET Framework, and is the successor to Microsoft's Active Server Pages ...
- Windows FormsWindows FormsWindows Forms is the name given to the graphical application programming interface included as a part of Microsoft .NET Framework, providing access to native Microsoft Windows interface elements by wrapping the extant Windows API in managed code...
- Java Class LibraryJava Class LibraryThe Java Class Library is a set of dynamically loadable libraries that Java applications can call at run time. Because the Java Platform is not dependent on any specific operating system, applications cannot rely on any of the existing libraries...
- Standard libraryStandard libraryA standard library for a programming language is the library that is conventionally made available in every implementation of that language. In some cases, the library is described directly in the programming language specification; in other cases, the contents of the standard library are...
Other capabilities of the .NET framework
- Windows Presentation FoundationWindows Presentation FoundationDeveloped by Microsoft, the Windows Presentation Foundation is a computer-software graphical subsystem for rendering user interfaces in Windows-based applications. WPF, previously known as "Avalon", was initially released as part of .NET Framework 3.0. Rather than relying on the older GDI...
(WPF) - Windows Communication FoundationWindows Communication FoundationThe Windows Communication Foundation , previously known as "Indigo", is an application programming interface in the .NET Framework for building connected, service-oriented applications.-The architectures:...
(WCF) - Windows Workflow FoundationWindows Workflow FoundationWindows Workflow Foundation is a Microsoft technology that provides an API, an in-process workflow engine, and a rehostable designer to implement long-running processes as workflows within .NET applications...
(WWF)
External links
- .NET Framework Developer Center Microsoft Developer Network (MSDN).
- Base Class Libraries Community More information and FAQs about the BCL.
- .NET Framework 3.5 namespaces
- MSDN BCL Documentation
- BCLTeam's WebLog