I\'m trying to add a WPF ResourceDictionary to a C# project that was created a while ago. The project was not originally a WPF project, but now I need to include some WPF re
I think your best bet is to create a new WPF project and copy everything across. If it is a very large project (and you are feeling adventurous) you might open the XML of the project files (Unload the project, then edit the original csproj file in XML)

Then copy across the ItemGroup sections, and ensure the corresponding source files exist under the new project directory. Good luck!