What is the difference between WPF and Silverlight application ? Are they the same ?
WPF is essentially the replacement to Winforms in that it is a desktop application platform built on the .Net (3+) platform.
Silverlight represents a subset of WPF that is delivered through a browser plug-in, much like Flash/Flex.
Silverlight (codenamed WPF/E) is a cross-platform, cross-browser, browser plugin which contains WPF-based technology (including XAML)[17] that provides features such as video, vector graphics, and animations to multiple operating systems including Windows Vista, Windows XP, and Mac OS X, with Microsoft sanctioned 3rd party developers working ports for Linux distributions.[18] Specifically, it is currently provided as an add-on for Mozilla Firefox, Internet Explorer 6 and above, and Apple Safari. Silverlight and WPF only share the XAML presentation layer.
WPF is based off of the desktop CLR which is the full version of the CLR.
Silverlight is based on a much smaller and more compact CLR which provides a great experience but does not have the full breadth of CLR features. It also has a much smaller version of the BCL.
Silverlight is a subset of WPF. Once it was known as WPF/E (WPF everywhere). In fact, the base framework is similar, but not the same.
See this for further information: Silverlight "WPF/E" first steps: Getting started with simple analog clock, Introduction - What is WPF/E?
Matthias