Framework Class Library

{{Short description|Standard library of Microsoft's .NET Framework}}

{{Use mdy dates|date=January 2019}}

{{Use American English|date=January 2019}}

The Framework Class Library (FCL) is a component of Microsoft's .NET Framework, the first implementation of the Common Language Infrastructure (CLI). In much the same way as Common Language Runtime (CLR) implements the CLI Virtual Execution System (VES), the FCL implements the CLI foundational Standard Libraries. As a CLI foundational class libraries implementation, it is a collection of reusable classes, interfaces, and value types, and includes an implementation of the CLI Base Class Library (BCL).{{cite web |title=.NET Core vs .NET Framework: How to Pick a .NET Runtime for an Application |url=https://stackify.com/net-core-vs-net-framework/ |website=Stackify |access-date=2019-06-24}}

With Microsoft's move to .NET Core, the CLI foundational class libraries implementation is known as CoreFX instead of Framework Class Library.