.NET Libraries

Open-source libraries make it easier for developers to create and manage their apps by reducing the amount of work they have to do. We'll go over some of the most useful.NET Core libraries that every developer should know in this article.

.NET often pronounced as 'dot-net,' is a quintessential framework featuring several editors, languages, and libraries used by C++/CLI programmers every day. .NET libraries or .NET Class Libraries are a massive collection of classes that serve specific purposes; they are predefined or pre-written code that supports both simple and complex data structures.

In this blog, readers will come across essential Libraries in .NET to better understand the framework. .NET Class libraries are meant for encryption, security, and access to the database. To compete with other frameworks, Microsoft has turned numerous segments of .NET into open-source licenses, allowing developers to download, study, and contribute to the source code's development.

List of .Net Libraries - Table of Content

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#1. Framework Class Library

The .NET Framework Class Library (FCL) features hundreds of structures and classes which are confined to namespaces in the form of a hierarchy. The C++/CLI developers and programmers make use of these classes as well as structures regularly.

As the Frame class library is massive, there is a myth that programmers often get lost while exploring. The myth is vague and indefinite as Framework Class Library is well organized, self-documenting, and easy to use. Once you get an overall understanding of the very essence of Framework Class Library, the properties, namespaces, methods, variable names, and properties will make proper sense. 

The single-most exception that experts have found in the Framework Class Library is that the library is wrapped around native classes. The FCL is a language-independent library that suggests programmers can use any language for programs such as C#.NET, Visual Basic.NET, C++, and J#.NET. Additionally, programmers use any third-party language that fits with Common Language Specification or CLS.

.Net FCL generally forms an ideal base over which applications, components, and controls are built the .NET. Programmers use this class library to curate applications like Windows GUI, console applications, Windows services, ASP.NET applications, and service-oriented applications by utilizing Windows Communication, workflow-enabled applications, and XML Web Services, among others.

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.NET also features a reusable kind of FCL which provides a straightforward and easy-to-understand interface to programmers and developers as:

  • FCL has a rich self-documenting nature.
  • Developers do not need to have extensive knowledge to understand the entirety of the framework; instead, if developers have a mediocre learning curve, they can still work their way around the framework. The framework is already capable of optimizing and expediting the overall development process without a hiccup.
  • FCL also facilitates a hassle-free integration of third-party components.
  • At times, FCL also behaves in the form of a standard library, which can be utilized persistently by the core .NET languages, as well as, the CLC compilers or Common language compliant.

The FCL comprises the classes which extend the support to the functions mentioned below:

  • Object type
  • Base data types
  • Garbage collection
  • Data structures implementation
  • Network Communications
  • Data and security access, database connectivity.
Related Article - Overview of .Net Framework

Framework Class Library has been curated for providing services that share a resemblance with the Windows API. Windows API was utilized by programmers much before the curation of . NET. The .NET FCL is combined with the Common Language Runtime of the .NET framework that manages code execution.

The classes in FCL follow an objective model, which is often used by IL or Intermediate Language, which depends on single-most inheritance. Moreover, the interfaces and classes are further grouped in the namespace to make accessibility an absolute treat.

In .NET, namespaces are hierarchy-based logical groups of classes related to each other. They can be utilized by language that targets the overall .NET framework. They are often found to be residing inside assemblies, the deployment units that comprise all the necessary details regarding interfaces, classes, as well as, structures. All the classes in .NET are segregated into the namespace. Some of the standard namespace in .NET FCL are:




Comprises the classes that handle events that are raised by OS. Further, it manipulates the overall registry of the system:


Features the classes which can handle the conventional mathematics invocation and oversees the supervision applications


Here the classes define collections of the objects like queues, lists, hash tables, arrays, and dictionaries


The classes in this namespace allow structure, classes, methods, and interfaces while delegating towards declaration and are further defined irrespective of their innate types


Classes here handle the overall database access


With this namespace, the classes handle direct access to the OLA DB database


Contains the classes which handle the accessibility to the database of Microsoft SQL Server


Allows programmers to seamlessly debug the application and at the same time trace the execution of the application


Classes in the namespace have access to the Active Directory


Classes here handle the functionality of GDI+ graphics


Classes handle the advanced-level vector graphics and two-dimensional functionality

System::Drawing: Imaging

Handles the advanced-level GDI+ imaging operability


Operates custom printing


The classes define information related to cultures like currency, numbers, and language


Classes oversee the writing and reading of data files and streams


Classes handle the protocols and services which are generally found on the network


Comprises of the classes that examine methods, loaded types, and fields while dynamically invoking and creating types


Classes here creates, manage, and store several culture-specific resources


Classes aid in accessing native APIs and COM objects


Classes aid in the configuration and creation of the distributed applications


Classes handle the overall security system in CLR


Classes handle the multithreaded programming:


Classes oversee the communication between a server and a browser


Features the classes that aid in the curation and deployment of emails via SMTP mail


Handles the overall security of ASP.NET in web-based applications


Classes aid in the curation and utilization of Web Services


Classes here create the controlling module alongside pages in many web applications


Classes aid in the creation of applications based on Windows


Classes here handle XML.

#2. Base Class Library

The base class library is also regarded as a class library or CL. It is a popular subset of the FCL. BCL is a culmination of the reusable type of libraries integrated with CLR, as mentioned earlier. It is CLS-compliant and has incredible accessibility.

It provides the types and classes which are useful to execute day-to-day functioning such as dealing with conventional and string kinds of database connections and IO operations. Generally, BCL can be put into use to curate any type of software from scratch.

BCL is a revolutionary library that uses ASP.NET to build REST services and websites alongside WCF for curating distributed systems, and WPF for building GUI applications for desktops, among others. Base class libraries create avenues for developers to interact with file systems and directories on any computer. Programmers can also use ADO.NET to establish communication with relational databases.

BCL features core types in its system namespace. The namespaces are the most fundamental in nature, such as System.DateTime, System.Diagnostics, System, System.Runtime.Serialization, System.Resources, System.Data, System.String, System.Text, among others.

Related Article: Advanced .Net Interview Questions

#3. Platform-Specific Class Libraries

These libraries are confined to a single-most .NET implementation. For instance, the most sought-after .NET Framework on the Windows OS is the perfect example of Platform-Specific Class Libraries. So far, this is also why platform-specific class libraries take up significant dependencies directly on the known environment for execution.

Moreover, the environment further exposes a familiar set of APIs such as the OS APOs and . NET. It also maintains and exposes the expected state, such as the Windows registry.

Programmers and developers who are well-versed in creating this library can completely exploit the fundamental platform. However, these libraries would only run on a specific platform, further making the platform check on other types of conditional code.

The platform-specific libraries are the primary class libraries for .NET Framework. Given that many .NET implementations have come into being, the platform-specific is still dominant among its competitors.

#4. Standard Class Libraries

The .NET Standard libraries are the replacement of both portable libraries and platform-specific libraries. Technically, they offer the same functionalities as the platform-specific, and at the same time, they also share the traits of portable specific libraries as they support all platforms. 

.NET stand class exposes a definite set of library contracts. The implementations should support either entirely or not at all. Hence, the standard class libraries are curated in such a way that it supports .NET Standard contracts.

The best thing about this library is Standard Class doesn’t reveal the full functionality of the .NET framework or its goal. However, they tend to expose a significant number of APIs compared to the Portable Class Libraries. In time, more APIs are going to be added to the library.

The platforms which support the Standard Class LIbraries are:

  • .NET Framework
  • .NET Core
  • Mono
  • Universal Windows Platform or UWP
  • Xamarin.Mac, Xamarin.Android, Xamarin.iOS
  • Windows Phone
  • Windows
  • Windows Phone Silverlight.

#5. Portable Class Libraries

These libraries are supported on numerous .NET implementations allowing them to depend on a known execution environment. It enables programmers to build and also write managed assemblies that support cross-platform integration.

Moreover, programmers have the liberty to create classes comprising codes that you can share across several projects like business logic and then reference the classes from projects of distinctive nature.

Developers could find the following assemblies in Portable Class Library:

  • System.dll
  • mscorlib.dll
  • System.Xml.dll
  • System.Core.dll
  • System.Net.dll
  • System.ComponentModel.Composition.dll
  • System.ServiceModel.dll
  • System.Runtime.Serialization.dll
  • System.Windows.dll (from Silverlight)
  • System.Xml.Serialization.dll.

At the time of curating a library, developers can choose a pogrom of their choice. However, the platform configuration must support Windows Phone 8.0+ and .NET Framework 4.5+. If you as a developer decide to support more platforms, you’ll have fewer platform assumptions and significantly fewer APIs.

At first, this characteristic could be incredibly confusing as people tend to think more is better; however, the shortcoming lies in supported platforms with fewer APIs.

Related Article: C# Interview Questions

#6. Mono Class Libraries

Mono comprises Standard Class, Portable Class, and Platform-specific class libraries, which is why it is regarded as the perfect cross-platform implementation of the .NET Framework. The platform-specific libraries on .NET Framework can efficiently work on Mono runtime without being recompiled or modified.

The remarkable characteristics and classification of Mono existed even before the inception of the Portable Class Libraries; hence developers found Mono a to-go choice for enabling cutting-edge binary portability between the Mono Class and the .NET Framework.

These are some of the necessary libraries that pave the way to a whole new world of programming and developing on the .NET Framework. The more you learn about libraries, the more you’ll ace in the field of programming and development.

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Last updated: 03 Apr 2023
About Author

Usha Sri Mendi is a Senior Content writer with more than three years of experience in writing for Mindmajix on various IT platforms such as Tableau, Linux, and Cloud Computing. She spends her precious time on researching various technologies, and startups. Reach out to her via LinkedIn and Twitter.

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