Introduction to WPF and WF with Framework 4.6Introduction to WPF and WF with Framework 4. 6 Windows Presentation Foundation (or WPF) is a graphical subsystem for rendering user interfaces in Windows based applications by Microsoft. WPF, previously known as "Avalon", was initially released as part of . NET Framework 3. 0. Rather than relying on the older GDI subsystem, WPF uses DirectX.