Best practices for creating both mouse and touch-o

Question

There is a need to develop WPF application which will support both mouse and touch input. I'm looking for an approach that will enable maintaining single codebase and minimize pain to implement that. Some framework or build configuration maybe - something like Project Linker + preprocessor directives scenario that is used to multi-target both WPF and Silverlight platforms in single project. Thanks in advance.
edit Sample scenario : application has control that allows user upload multiple photos onto server. File selection box supports drag'n'drop with mouse, also it has to support some gesture to add new files.

Answer 1

Check this Drag and Drop Library.