With System.in, enter is the only key press you can detect as soon as it happens. If you call readLine() it will return as soon as the user hits enter. The user may have typed other things as well, but you can ignore them.
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com
subject: How to detect ENTER key from console app?