The DotNet comes in three versions: DotNet Framework, DotNet Core, and Xamarin. These implementations combined are called the DotNet development platform. Every one of them contains frameworks and libraries to build various applications.

DotNet Framework

The DotNet Framework, released in 2002, is the first and oldest implementation of the platform. It includes three main application models –  Windows Forms, WPF, ASPDotNet Forms – and Base Class Library.

Windows Presentation Foundation (WPF) is a User Interface framework used for designing graphical interfaces, mainly for desktop client applications on Windows OS. WPF uses the efficiency of the Extensible Application Markup Language (XAML).

Windows Forms is a Graphical User Interface class library within DotNet Framework. Windows Forms are used to build desktop applications with vibrant graphics that are easy to update and deploy.

ASPDotNet. While the past two components are designed for desktop engineering, ASPDotNet is used to build dynamic web applications and websites. There is a Common Language Runtime (CLR) in its core that allows developers to write ASPDotNet code using different DotNet languages.

Base Class Library (BCL) grants the most common functionality, like classes in namespaces. It is the core of the Framework Class Library (FCL), a set of reusable interfaces, classes, and value types that are tightly combined with the Common Language Runtime (CLR). The combination of CLR and FCL constitutes the DotNet Framework. The base class library also includes ADODotNet, data access technology used by developers to access databases.

DotNet Framework supports only Windows-based devices, and the need for a cross-platform package occurred.

DotNet Core

DotNet Core was released in 2016. It’s a cross-platform re-build of the DotNet Framework. Engineers can now use the product on OS X and Linux and build applications that aren't certainly tied to the Windows OS. The latest system aims at conquering the cloud space as some providers like Digital Ocean are Linux-driven. Not only DotNet Core is cross-platform, but also its different versions can be installed side-by-side on the same device. DotNet Core includes the Universal Windows Platform (UWP) and ASPDotNet Core.

Universal Windows Platform (UWP) is an API build by Microsoft and used to develop the universal apps that run on all compatible Microsoft Windows devices, i.e., Windows Phone, Windows,  and HoloLens.

ASPDotNet Core is a re-build of ASPDotNet that happened to be a more modular framework than its predecessor. ASPDotNet Core allows you to create a mobile backend,  services, and web apps. It's also cross-platform and runs on Linux, OS X, and Windows.

Xamarin

The third Version is called Xamarin and is used for Mac products and mobile applications. Xamarin was built independently from Microsoft and was a proprietary product until Microsoft acquired it in 2016, making a fully open-source branch of the DotNet platform. Xamarin uses the single runtime, and a version of the DotNet Framework adapted to work with APIs for Xamarin, iOS, and Android, Mac. Overview of this product.

All runtimes use an average infrastructure that makes the entire ecosystem work. It provides runtime languages, components, and compilers.