Projections, Projections Everywhere - C++17 comes to Town

In a nutshell.

1. C++/CX ("component extensions") are extensions to C++ to create  Windows Runtime (WinRT) applications in as native a C++ style as possible
2. C++/WinRT is the recommended alternative to interacting with WinRT (available in the Windows 10 SDK from version 1803 onwards) and is C++17 language compatible
3. Projections are thee new name for bindings

Roughly speaking, WinRT is the Win32 API ported from C to C++, with a whole load of new stuff for Windows 10 and beyond.

The Two Sets of APIs to Build Windows Runtime Apps

These APIs are Windows Runtime and WinJS.  The latter enables you to build HTML/JavaScript applications with equivalent functionality to XAML (specifically the Windows.UI.Xaml namespace equivalent functionality).

WinJS.Application provides application level functionality such as activation, storage and application events. When you create a new Windows JavaScript application, you'll see this namespace referenced in the default.js under the js folder of your solution.

Programming at the API Boundary in Windows 8: C++ Component Extensions

The WinRT - What CX is All About

C++/CX (Component Extensions) borrows from C++/CLI but targets the Windows Runtime (WinRT) and native code instead of the CLR and managed code.

It is not Managed C++, though it looks a bit like it.  Neither is it perfectly obedient, standard C++. It is C++ with a bit of "Microsoft spice" added to the fray.

Can thou givest an example of "Microsoft Spice" added to the fray?

Among the so-called "component extensions" is support for partial classes, mainly for auto-merging generated code with developer code. Partial classes are not part of the C++ standard (at least, not as part of C++11).

The entry point - notion of the "ref class"

To use "component extensions" you must declare your class as a "ref class" e.g. public ref class SuperClass. To make it partial, you can whack a partial on the front: partial ref class SuperClass.

C++/CX also supports runtime generics (versus compile-time generics in the STL). However, support for compile time generics remains in place.