The .NET Framework class library provides the following namespaces, which are documented in detail in this reference.
- Accessibility
Contains types that are part of a managed wrapper for the Component Object Model (COM) accessibility interface.
- Microsoft.Aspnet.Snapin
Contains classes that are necessary for the ASP.NET management console application to interact with the Microsoft Management Console (MMC).
- Microsoft.Build.BuildEngine
Contains the classes that represent the MSBuild engine.
- Microsoft.Build.Conversion
Contains types that Visual Studio uses to convert project files.
- Microsoft.Build.Framework
Contains classes that make up the tasks, loggers, and events of MSBuild.
- Microsoft.Build.Tasks
Contains the implementation of all tasks shipping with MSBuild.
- Microsoft.Build.Tasks.Deployment.Bootstrapper
Contains classes used internally by MSBuild.
- Microsoft.Build.Tasks.Deployment.ManifestUtilities
Contains classes used internally by MSBuild.
- Microsoft.Build.Tasks.Hosting
Contains classes used internally by MSBuild.
- Microsoft.Build.Tasks.Windows
Contains classes used internally by MSBuild.
- Microsoft.Build.Utilities
Provides helper classes that you can use to create your own MSBuild loggers and tasks.
- Microsoft.CSharp
Contains classes that support compilation and code generation using the C# language.
- Microsoft.Ink
Contains types that implement digital ink on the Tablet PC.
- Microsoft.JScript
Contains classes that support compilation and code generation using the JScript language.
- Microsoft.ServiceModel.Channels.Mail
Contains classes that support programming applications on the .NET Compact Framework and on the desktop using the Exchange Server mail transport based on Windows Communication Foundation (WCF).
- Microsoft.ServiceModel.Channels.Mail.ExchangeWebService
Contains classes that provide the implementation of the Microsoft Exchange Server mail transport on the desktop by using the .NET Framework.
- Microsoft.ServiceModel.Channels.Mail.WindowsMobile
Contains classes that provide the implementation of the Microsoft Exchange Server mail transport on Windows Mobile devices that use the .NET Compact Framework.
- Microsoft.SqlServer.Server
Contains classes that are specific to the integration of the.NET Framework common language runtime (CLR) component into Microsoft SQL Server, and the SQL Server database engine process execution environment.
- Microsoft.StylusInput
Contains types that handle the stylus packet data from a digitizer in real time.
- Microsoft.StylusInput.PluginData
Contains types that represent the data passed to RealTimeStylus plug-ins.
- Microsoft.VisualBasic
Contains classes that support compilation and code generation using the Visual Basic language.
- Microsoft.VisualBasic.ApplicationServices
Contains types that support the Visual Basic Application Model and provide access to application information.
- Microsoft.VisualBasic.Compatibility.VB6
Contains types used by tools for upgrading from Visual Basic 6.0 to Visual Basic .NET.
- Microsoft.VisualBasic.CompilerServices
Contains internal-use only types that support the Visual Basic compiler.
- Microsoft.VisualBasic.Devices
Contains types that support the My objects related to devices in Visual Basic.
- Microsoft.VisualBasic.FileIO
Contains types that support the My file system object in Visual Basic.
- Microsoft.VisualBasic.Logging
Contains types that support the My logging objects in Visual Basic and provides a simple log listener that directs logging output to file.
- Microsoft.VisualBasic.MyServices
Contains types that support My in Visual Basic.
- Microsoft.VisualBasic.MyServices.Internal
Contains internal-use only types that support My in Visual Basic.
- Microsoft.VisualC
Contains types that support the Visual C++ compiler.
- Microsoft.VisualC.StlClr
Contains types that implement the STL/CLR Library.
- Microsoft.VisualC.StlClr.Generic
Contains types that implement the generic interface to the STL/CLR Library.
- Microsoft.Vsa
Contains interfaces that enable you to integrate script for the .NET Framework script engines into applications, and to compile and execute code at run time.
- Microsoft.Web.Administration
Contains classes for administering Internet Information Services (IIS) Manager.
- Microsoft.Web.Management.Client
Contains classes for developing tools that are displayed in IIS Manager.
- Microsoft.Web.Management.Client.Extensions
Contains classes to extend features in IIS Manager.
- Microsoft.Web.Management.Client.Win32
Contains user interface classes for creating Windows Forms for tools that are displayed in IIS Manager.
- Microsoft.Web.Management.Features.Administrators
Contains a class that identifies an administrator module.
- Microsoft.Web.Management.Features.Delegation
Contains a class that identifies a delegation module.
- Microsoft.Web.Management.Features.Service
Contains a class that identifies a management service module.
- Microsoft.Web.Management.Host
Contains an interface that identifies the host of a management unit.
- Microsoft.Web.Management.Host.Shell
Contains classes that start IIS Manager and pass information to it.
- Microsoft.Web.Management.Server
Contains types that implement the server portion of a management feature in IIS Manager.
- Microsoft.Win32
Provides two types of classes: those that handle events raised by the operating system and those that manipulate the system registry.
- Microsoft.Win32.SafeHandles
Contains classes that are abstract derivations of safe handle classes that provide common functionality supporting file and operating system handles.
- Microsoft.Windows.Themes
Provides exposure to the set of themes defined by Windows Presentation Foundation (WPF).
- Microsoft.WindowsCE.Forms
Contains classes for developing Pocket PC and Smartphone Windows Forms applications using the .NET Compact Framework.
- Microsoft.WindowsMobile.DirectX
Contains classes for developing DirectX applications on devices with the .NET Compact Framework.
- Microsoft.WindowsMobile.DirectX.Direct3D
Contains classes for developing Direct3D applications on devices with the .NET Compact Framework.
- System
Contains fundamental classes and base classes that define commonly used value and reference data types, events and event handlers, interfaces, attributes, and processing exceptions. Other classes provide services supporting data type conversion, method parameter manipulation, mathematics, remote and local program invocation, application environment management, and supervision of managed and unmanaged applications.
- System.AddIn
Contains an attribute for identifying add-ins.
- System.AddIn.Contract
Contains types that provide the basis for communication between components that are updated independently.
- System.AddIn.Contract.Automation
Contains types that components use to access type information and invoke type members.
- System.AddIn.Contract.Collections
Contains types used to implement collection classes for add-in development.
- System.AddIn.Hosting
Provides types for discovering, registering, activating, and controlling add-ins.
- System.AddIn.Pipeline
Provides classes for constructing the communication pipeline between a host application and an add-in.
- System.CodeDom
Contains classes that can be used to represent the elements and structure of a source code document. These elements can be used to model the structure of a source code document that can be output as source code in a supported language using the functionality provided by the System.CodeDom.Compiler namespace.
- System.CodeDom.Compiler
Contains types for managing the generation and compilation of source code in supported programming languages. Code generators can each produce source code in a particular programming language based on the structure of Code Document Object Model (CodeDOM) source code models consisting of elements provided by the System.CodeDom namespace.
- System.Collections
Contains interfaces and classes that define various collections of objects, such as lists, queues, bit arrays, hashtables and dictionaries.
- System.Collections.Generic
Contains interfaces and classes that define generic collections, which enable users to create strongly typed collections that provide better type safety and performance than non-generic strongly typed collections.
- System.Collections.ObjectModel
Contains classes that can be used as collections in the object model of a reusable library. Use these classes when properties or methods return collections.
- System.Collections.Specialized
Contains specialized and strongly typed collections; for example, a linked list dictionary, a bit vector, and collections that contain only strings.
- System.ComponentModel
Provides classes that are used to implement the run-time and design-time behavior of components and controls. This namespace includes the base classes and interfaces for implementing attributes and type converters, binding to data sources, and licensing components.
- System.ComponentModel.Design
Contains classes that developers can use to build custom design-time behavior for components and user interfaces for configuring components at design time. The design time environment provides systems that enable developers to arrange components and configure their properties.
- System.ComponentModel.Design.Data
Contains classes for implementing design-time behavior of data-related components.
- System.ComponentModel.Design.Serialization
Provides types that support customization and control of serialization at design time.
- System.Configuration
Contains the types that provide the programming model for handling configuration data.
- System.Configuration.Assemblies
Contains classes that are used to configure an assembly.
- System.Configuration.Install
Provides classes that enable you to write custom installers for your own components. The Installer class is the base class for all custom installers in the .NET Framework.
- System.Configuration.Provider
Contains the base classes shared by both server and client applications to support a pluggable model to easily add or remove functionality.
- System.Data
Contains classes that constitute most of the ADO.NET architecture. The ADO.NET architecture enables you to build components that efficiently manage data from multiple data sources.
- System.Data.Common
Contains classes shared by the .NET Framework data providers. A .NET Framework data provider describes a collection of classes used to access a data source, such as a database, in the managed space.
- System.Data.Design
Contains classes that can be used to generate a custom typed dataset.
- System.Data.Linq
Contains classes that support interaction with relational databases in LINQ to SQL applications.
- System.Data.Linq.Mapping
Contains classes that are used to generate a LINQ to SQL object model that represents the structure and content of a relational database.
- System.Data.Odbc
Contains classes that encapsulate the .NET Framework Data Provider for ODBC. The .NET Framework Data Provider for ODBC describes a collection of classes used to access an ODBC data source in the managed space.
- System.Data.OleDb
Contains classes that encapsulate the .NET Framework Data Provider for OLE DB. The .NET Framework Data Provider for OLE DB describes a collection of classes used to access an OLE DB data source in the managed space.
- System.Data.OracleClient
Contains classes that encapsulate the .NET Framework Data Provider for Oracle. The .NET Framework Data Provider for Oracle describes a collection of classes used to access an Oracle data source in the managed space.
- System.Data.Sql
Contains classes that support SQL Server-specific functionality. The API extensions in this class add to the .NET Framework Data Provider for SQL Server (System.Data.SqlClient).
- System.Data.SqlClient
Contains classes that encapsulate the .NET Framework Data Provider for SQL Server. The .NET Framework Data Provider for SQL Server describes a collection of classes used to access a SQL Server database in the managed space.
- System.Data.SqlServerCe
Describes a collection of classes that can be used to access a database in SQL Server CE from Windows CE-based devices in the managed environment. With this namespace you can create SQL Server CE databases on a device and also establish connections to SQL Server databases that are on a device or on a remote server.
- System.Data.SqlTypes
Contains classes for native data types within SQL Server. These classes provide a faster alternative to other data types. Using the classes in this namespace helps prevent type conversion errors caused in situations where loss of precision could occur. Because other data types are converted to and from SqlTypes behind the scenes, explicitly creating and using objects within this namespace results in faster code as well.
- System.Deployment.Application
Provides types to create custom upgrade behavior in ClickOnce applications.
- System.Diagnostics
Provides classes that enable you to interact with system processes, event logs, and performance counters. This namespace also provides classes that let you debug your application and trace the execution of your code.
- System.Diagnostics.CodeAnalysis
Contains classes for interaction with code analysis tools. Code analysis tools are used to analyze code for conformance to coding conventions such as naming or security rules.
- System.Diagnostics.Design
Contains classes that can be used to extend design-time support for application monitoring and instrumentation.
- System.Diagnostics.Eventing
Contains types to support implementation of an application on Windows Vista. The instrumentation, when enabled, logs event data to the Event Tracing for Windows (ETW) tracing subsystem.
- System.Diagnostics.Eventing.Reader
Contains types to support reading from and managing event logs.
- System.Diagnostics.PerformanceData
Contains classes that are used to provide counter data, which expose performance metrics to consumers.
- System.Diagnostics.SymbolStore
Provides classes that enable you to read and write debug symbol information, such as source line to Microsoft intermediate language (MSIL) maps. Compilers targeting the .NET Framework can store the debug symbol information into programmer's database (PDB) files. Debuggers and code profiler tools can read the debug symbol information at run time.
- System.DirectoryServices
Provides easy access to Active Directory from managed code. The namespace contains two component classes, DirectoryEntry and DirectorySearcher, which use the Active Directory Services Interfaces (ADSI) technology. ADSI is the set of interfaces that Microsoft provides as a flexible tool for working with a variety of network providers. ADSI gives the administrator the ability to locate and manage resources on a network with relative ease, regardless of the network's size.
- System.DirectoryServices.AccountManagement
Provides uniform access and manipulation of user, computer, and group security principals across multiple principal stores.
- System.DirectoryServices.ActiveDirectory
Provides a high-level abstraction object model that builds around Active Directory directory service tasks. The Active Directory directory service concepts such as forest, domain, site, subnet, partition, and schema are part of the object model.
- System.DirectoryServices.Protocols
Provides the methods defined in the Lightweight Directory Access Protocol (LDAP) version 3 and Directory Services Markup Language (DSML) version 2.0 standards.
- System.Drawing
Provides access to GDI+ basic graphics functionality. More advanced functionality is provided in the System.Drawing.Drawing2D, System.Drawing.Imaging, and System.Drawing.Text namespaces.
- System.Drawing.Design
Contains classes that extend design-time user interface (UI) logic and drawing. You can further extend this design-time functionality to create custom toolbox items, type-specific value editors that can edit and graphically represent values of their supported types, or type converters that can convert values between certain types. This namespace provides the basic frameworks for developing extensions to the design-time UI.
- System.Drawing.Drawing2D
Provides advanced two-dimensional and vector graphics functionality. This namespace includes the gradient brushes, the Matrix class (used to define geometric transforms), and the GraphicsPath class.
- System.Drawing.Imaging
Provides advanced GDI+ imaging functionality. Basic graphics functionality is provided by the System.Drawing namespace.
- System.Drawing.Printing
Provides print-related services. Typically, you create a new instance of the PrintDocument class, set the properties that describe what to print, and call the Print method to actually print the document.
- System.Drawing.Text
Provides advanced GDI+ typography functionality. Basic graphics functionality is provided by the System.Drawing namespace. The classes in this namespace enable users to create and use collections of fonts.
- System.EnterpriseServices
Provides an important infrastructure for enterprise applications. COM+ provides a services architecture for component programming models deployed in an enterprise environment. This namespace provides .NET Framework objects with access to COM+ services, making the .NET Framework objects more practical for enterprise applications.
- System.EnterpriseServices.CompensatingResourceManager
Provides classes that enable you to use a Compensating Resource Manager (CRM) in managed code. A CRM is a service provided by COM+ that enables you to include non-transactional objects in Microsoft Distributed Transaction Coordinator (DTC) transactions. Although CRMs do not provide the capabilities of a full resource manager, they do provide transactional atomicity (all-or-nothing behavior) and durability through the recovery log.
- System.Globalization
Contains classes that define culture-related information, including the language, the country/region, the calendars in use, the format patterns for dates, currency, and numbers, and the sort order for strings. These classes are useful for writing globalized (internationalized) applications.
- System.IdentityModel.Claims
Contains types that support the use of claims in the Extensible Identity Model.
- System.IdentityModel.Policy
Contains types to build or use authorization policies in Windows Communication Foundation (WCF).
- System.IdentityModel.Selectors
Contains the types that provide security tokens for outgoing SOAP messages and that authenticate security tokens in incoming SOAP messages.
- System.IdentityModel.Tokens
Contains the types that are related to the predefined security tokens that ship with Windows Communication Foundation (WFC).
- System.IO
Contains types that enable synchronous and asynchronous reading and writing on data streams and files.
- System.IO.Compression
Contains classes that provide basic compression and decompression for streams.
- System.IO.IsolatedStorage
Contains types that support the creation and use of isolated stores. With these stores, you can read and write data that less trusted code cannot access and help prevent the exposure of sensitive information that can be saved elsewhere on the file system. Data is stored in compartments that are isolated by the current user and by the assembly in which the code exists.
- System.IO.Log
Contains types for implementing a custom diagnostic logging or transaction processing system.
- System.IO.Packaging
Contains types that support storage of multiple data objects in a single container.
- System.IO.Pipes
Contains types that provide a means for interprocess communication through anonymous and/or named pipes.
- System.IO.Ports
Contains classes that control serial ports, providing a framework for synchronous and event-driven I/O, access to pin and break states, access to serial driver properties, and enumerations for specifying port characteristics.
- System.Linq
Contains classes and interfaces that support queries that use Language-Integrated Query (LINQ).
- System.Linq.Expressions
Contains types that enable language-level code expressions to be represented as objects in the form of expression trees.
- System.Management
Provides access to a rich set of management information and management events about the system, devices, and applications instrumented to the Windows Management Instrumentation (WMI) infrastructure.
- System.Management.Instrumentation
Provides the classes necessary for instrumenting applications for management and exposing their management information and events through WMI to potential consumers.
- System.Media
Contains classes for playing sound files and accessing system sounds.
- System.Messaging
Provides classes that enable you to connect to, monitor, and administer message queues on the network and send, receive, or peek messages.
- System.Messaging.Design
Contains classes that can be used to extend design-time support for System.Messaging classes.
- System.Net
Provides a simple programming interface for many of the protocols used on networks today. The WebRequest and WebResponse classes form the basis of what are called pluggable protocols, an implementation of network services that enables you to develop applications that use Internet resources without worrying about the specific details of the individual protocols.
- System.Net.Cache
Defines the types and enumerations used to define cache policies for resources obtained using the WebRequest and HttpWebRequest classes.
- System.Net.Configuration
Contains classes that applications use to programmatically access and update configuration settings for the System.Net namespaces.
- System.Net.Mail
Contains classes used to send electronic mail to a Simple Mail Transfer Protocol (SMTP) server for delivery.
- System.Net.Mime
Contains types that are used to represent Multipurpose Internet Mail Exchange (MIME) headers. These types are used with the types in the System.Net.Mail namespace to specify Content-Type, Content-Disposition and Content-transfer-Encoding headers when sending e-mail using the SmtpClient class.
- System.Net.NetworkInformation
Provides access to network traffic data, network address information, and notification of address changes for the local computer. The namespace also contains classes that implement the Ping utility. You can use Ping and related classes to check whether a computer is reachable across the network.
- System.Net.Security
Contains types that provide network streams for secure communication between hosts.
- System.Net.PeerToPeer
Provides access to peer networking functionality.
- System.Net.PeerToPeer.Collaboration
Provides types that enhance peer-to-peer networking functionality and provide capabilities for serverless managed collaboration sessions.
- System.Net.Security
Provides network streams for secure communications between hosts.
- System.Net.Sockets
Provides a managed implementation of the Windows Sockets (Winsock) interface for developers who need to help control access to the network.
- System.Printing
Contains types to support printing.
- System.Printing.IndexedProperties
Contains classes that provide access to the properties of print system objects without using reflection, and enable rapid copying of the property settings to another object of the same type.
- System.Printing.Interop
Provides types to support interconversion of managed PrintTicket objects and unmanaged Graphics Device Interface (GDI) DEVMODE structures.
- System.Reflection
Contains classes and interfaces that provide a managed view of loaded types, methods, and fields, with the ability to dynamically create and invoke types.
- System.Reflection.Emit
Contains classes that enable a compiler or tool to emit metadata and Microsoft intermediate language (MSIL) and optionally generate a PE file on disk. The primary clients of these classes are script engines and compilers.
- System.Resources
Provides classes and interfaces that enable developers to create, store, and manage various culture-specific resources used in an application.
- System.Resources.Tools
Contains the StronglyTypedResourceBuilder class, which provides support for strongly typed resources. Beginning with the .NET Framework version 2.0, this compile-time feature encapsulates access to resources by creating classes that contain a set of static read-only (get) properties, thus making it easier to consume resources.
- System.Runtime
Contains advanced types that support diverse namespaces such as System, the Runtime namespaces, and the Security namespaces.
- System.Runtime.CompilerServices
Provides functionality for compiler writers who use managed code to specify attributes in metadata that affect the run-time behavior of the common language runtime. The classes in this namespace are for compiler writers use only.
- System.Runtime.ConstrainedExecution
Defines a set of types that enumerate and define a contract for reliability between the author of some code and the developers who take a dependency on that code. The types are intended for use in constrained execution regions (CERs) only.
- System.Runtime.Hosting
Contains advanced types that are used in application activation within application domains.
- System.Runtime.InteropServices
Provides a wide variety of members that support COM interop and platform invoke services. If you are unfamiliar with these services, see Interoperating with Unmanaged Code.
- System.Runtime.InteropServices.ComTypes
Contains methods that are definitions of COM functions for managed code. These functions replace the now-obsolete UCOM methods in the System.Runtime.InteropServices namespace.
- System.Runtime.InteropServices.Expando
Contains the IExpando interface, which lets you modify an object by adding or removing its members.
- System.Runtime.Remoting
Provides classes and interfaces that enable developers to create and configure distributed applications.
- System.Runtime.Remoting.Activation
Provides classes and objects that support server and client activation of remote objects.
- System.Runtime.Remoting.Channels
Contains classes that support and handle channels and channel sinks, which are used as the transport medium when a client calls a method on a remote object.
- System.Runtime.Remoting.Channels.Http
Contains channels that use the HTTP protocol to transport messages and objects to and from remote locations. By default, the HTTP channels encode objects and method calls in SOAP format for transmission, but other encoding and decoding formatter sinks can be specified in the configuration properties of a channel.
- System.Runtime.Remoting.Channels.Ipc
Defines a communication channel for remoting that uses the Interprocess Communication (IPC) system of the Windows operating system. Because it does not use network communication, the IPC channel is much faster than the HTTP and TCP channels, but it can only be used for communication between application domains on the same physical computer.
- System.Runtime.Remoting.Channels.Tcp
Contains channels that use the TCP protocol to transport messages and objects to and from remote locations. By default, the TCP channels encode objects and method calls in binary format for transmission, but other encoding and decoding formatter sinks can be specified in the configuration properties of a channel.
- System.Runtime.Remoting.Contexts
Contains objects that define the contexts all objects reside within. A context is an ordered sequence of properties that defines an environment for the objects within it. Contexts are created during the activation process for objects that are configured to require certain automatic services such synchronization, transactions, just-in-time (JIT) activation, security, and so on. Multiple objects can live inside a context.
- System.Runtime.Remoting.Lifetime
Contains classes that manage the lifetime of remote objects. Traditionally, distributed garbage collection uses reference counts and pinging for control over the lifetime of objects. This works well when there are a few clients per service, but does not scale well to thousands of clients per service. The remoting lifetime service associates a lease with each service, and deletes a service when its lease time expires. The lifetime service can take on the function of a traditional distributed garbage collector, and it also adjusts well when the numbers of clients per server increases.
- System.Runtime.Remoting.Messaging
Contains classes used to create and remote messages. The remoting infrastructure uses messages to communicate with remote objects. Messages are used to transmit remote method calls, to activate remote objects, and to communicate information. A message object carries a set of named properties, including action identifiers, envoy information, and parameters.
- System.Runtime.Remoting.Metadata
Contains classes and attributes that can be used to customize generation and processing of SOAP for objects and fields. The classes of this namespace can be used to indicate the SOAPAction, type output, XML element name, and the method XML namespace Uniform Resource Identifier (URI).
- System.Runtime.Remoting.Metadata.W3cXsd2001
Contains the XML Schema Definition (XSD) defined by the World Wide Web Consortium (W3C) in 2001. The XML Schema Part 2: Datatypes specification from W3C identifies format and behavior of various data types. This namespace contains wrapper classes for the data types that conform to the W3C specification. All date and time types conform to the ISO standards specification.
- System.Runtime.Remoting.MetadataServices
Contains the classes used by the Soapsuds.exe command line tool and the user code to convert metadata to and from XML schema for the remoting infrastructure.
- System.Runtime.Remoting.Proxies
Contains classes that control and provide functionality for proxies. A proxy is a local object that is an image of a remote object. Proxies enable clients to access objects across remoting boundaries.