.NET 5

Microsoft’s .NET platform and the C# programming language were formally introduced circa 2002 and have quickly become a mainstay of modern-day software development. The .NET platform enables a large number of programming languages (including C#, VB.NET, and F#) to interact with each other. A program written in C# can be referenced by another program written in VB.NET. More on this interoperability later in this chapter.

In 2016, Microsoft officially launched .NET Core. Like .NET, .NET Core allows languages to interop with each other (although a limited number of languages are supported). More important, this new framework is no longer limited to running on the Windows operating system, but can also run (and be developed) on iOS and Linux. This platform independence opened up C# to a much larger pool of developers. While cross-platform use of C# was supported prior to .NET Core, that was through various other frameworks such as the Mono project.