I am a veteran Delphi 6 programmer transitioning to C# development. My first project is a open source library that will have a minimal user interface since it is meant to be used as a Component primarily on desktop PCs running Visual Studio. My next project is going to be a Windows 8 phone app and I intend for that platform to be my primary focus for future C# development, not the desktop.
My concern is that I waste as little time as possible learning a presentation framework that will benefit or distract me from writing Windows 8 phone apps. The plethora of framework names I have already encountered include, WinForms, WPF (Windows Presentation Framework), Silverlight, Silverlight Mobile, Metro and there may be others.
Given my goal outlined in the first paragraph above, which is the correct framework to study for developing Windows 8 phone apps?
I read about the Portable Library Tools on this Stack Overflow thread:
https://stackoverflow.com/questions/5522355/windows-phone-7-wpf-sharing-a-codebase
But the reply by Simon Guindon seemed to indicate to me that it's not the best solution for writing a competitive Windows 8 phone app.