What is WinFX?
WinFX is a managed (CLR-based) API that extends the .NET Framework. However, it is accessible via MC++ to unmanaged applications. It encompasses all of the managed APIs that Microsoft will ship in Longhorn, including Avalon, Indigo, and WinFS, and .NET Frameworks.
It is broken down in to interface/data/communication layers which are Avalon/WinFS/Indigo respectively.
WinFX is the heart of Longhorn from which Avalon/WinFS/Indigo will all follow.
Content courtesy of Neowin.net
