Regex for a 19 character string that includes special characters

Question

I would like to create a regex that limits a string to 19 or 15 characters and also includes special character but out of order.

Examples are

847294729472903472c3c
 111 ( 3234) 3235
1234 + 1234

Answer 1

If a special character is any non-ascii letter or integer number, you can do the following:

new Regex("^((.{15})|(.{19}))$").IsMatch(text) && new Regex("[^a-zA-Z0-9]").IsMatch(text)

See on .NET fiddle: https://dotnetfiddle.net/vTyn7q