What is the difference between WPF and Silverlight?

Question

What is the difference between WPF and Silverlight?

Is it just the same as winforms vs asp as in desktop apps versus web app or is there an overlap?

Answer 1

WPF is a desktop API that is a replacement to the venerable pixel-based GDI Winforms library. It uses XML layout (XAML) and binding, partial classes and is no longer pixel-based (it deals in units so apps still work where the user has the DPI set differently).

Silverlight is a subset of WPF that runs within a browser, much like Flash.

Silverlight 3 extended its reach onto the desktop as a counter to Adobe Air so there isn't much of a gap between Silverlight and WPF to the point where one has to question the future of WPF. See Silverlight 3 might kill Windows Presentation Foundation.