How to catch pressing Alt+Shift outside my application (globally)?

Question

C++ / C#

Greetings!
I want to make a layout indicator floating on the screen.
It is necessary to track the layout change globally. Switching happens on Alt+Shift.
As far as I remember, there are difficulties with registering a global hotkey consisting only of modifier buttons.
Please share the code that allows you to catch Alt + Shift globally, outside of my application.
Thank you!

Answer 1

Your indicator will not work with this approach. Now the language is tied to each application, i.e. you can work with several applications at once and each of them will have its own layout and language active. Switching between applications, the language switches and the layout indicator.
Not to mention the fact that I now switch the language with the CAPS_LOCK key.

Answer 2

Needs to be tracked globally.

To track something globally, you need to install a hook.

Answer 3

https://www.codeproject.com/Articles/19004/A-Simpl...
Create an instance, add the buttons you want to listen to, and subscribe to the event