I'm currently working on a programming educational software and I still haven't figured out how to colorize some particular words (keywords like if,while,for,using,namespace and so on) in a RICHTEXTBOX.
I've tried this: Readonly richtextbox changing color of keyword C#
but it works only on WinForms. The methods like Action, Select and the properties of the class Color seem not to exist.
Example images: https://i.stack.imgur.com/xsjFP.jpg