It is not limited to C#. That page has samples for C#, VB, F# and C++ (look at the top-right of the page to change the language). However if you do not need to use managed (.Net) in C++ then you can use the original Rich Edit. And if you look at the right side of that page there is a Using Rich Edit Controls section and thee first page of that section is How to Create Rich Edit Controls.
If you are using MFC then see: