That regular expression will find any digit in a string. So, what you want to do is check the string to see if that regular expression returns any results. If it does, that means the string contains a digit. I don't want to make it too easy for you (as I expect you to do the learning and only come to us when you are running into a problem you can't seem to solve), so I will leave figuring out how to use the regular expression up to you. This should get you started: .Net Regular Expressions
Alternatively, you could just loop through each character in the string and check if it is a digit. Again, that should be extremely simple, so I'll leave that as an exercise for you to do.