Recently I was asked to investigate a scenario for a desktop C++ application. It was something I’d done before with C# and used a number of WinRT APIs. This meant I had to refresh myself in C++ which has changed again since the last time I used it!
I started with the latest C++/WinRT template so a lot of the plumbing is already set up for you. However there was a useful reference here with mappings for some common things from C# and how they appear in C++.
Of course if your starting point is an existing desktop C++ app there are a few steps you need to follow to add WinRT functionality. I found this reference useful.