The edit.com window you are showing appear to be developed with Turbo Vision, an old console gui library written by Borland many years ago.
Borland put the software in public domain and release its C++ sources. There is also a porting to Pascal, developed by the community, called Free Vision.
Unfortunately ,I don't think there is a porting or a wrapper to dot.net, so you have to write your own. Or, at least, you can look at the sources to get inspired...
