This whitepaper documents both the identical (or nearly so) functionality as well as the differences. WPF and Silverlight have many technological concepts in common: Dependency Properties, Data Binding, Custom Controls and Animation to name a few. In addition, this paper documents functionality implementations that may be available in only one technology or the other. For example, WPF implements a large library of controls for document handling, including printing and formatting large documents.
Finally, this whitepaper outlines some strategies in obtaining code reuse across both technologies. Due to minor differences in implementations of common elements, developers need to carefully plan their development in order to reuse code in both platforms. Of course, since certain functionality may not exist in one platform, developers may need to reduce the scope of the application in those cases.