NCrontab[1] is a library written in C# 3.0 that provides the following facilities:

• Parsing of crontab expressions
• Formatting of crontab expressions
• Calculation of occurrences of time based on a crontab schedule

NCron does parsing and calculation of occurrences as well. There is no reason for the two projects to overlap, and it should be easy to change NCron to use NCrontab in the relevant places.

[1] http://code.google.com/p/ncrontab/