Regex to validate length of alphanumeric string
.net, alphanumeric, c#, regex, validation
Solution
I would do it like this:
^(?!.* )(?=.*[\w-])[\w -]{1,10}$
This uses a negative look-ahead `(?!.* )` to assert there are not two consecutive spaces, and a positive look-ahead `(?=.*[\w-])` to assert it has at least one non-space character (I assume "empty" means "only spaces").
Note that if it can't be "empty", it can't be zero length, so the length range must be 1-10, not 0-10.
Of tiny note is the fact that you don't need to escape the dash in a character class if it's the first or last character.
Problem
I have the following regular expression: ``` ^[a-zA-Z0-9]+( [a-zA-Z0-9]+)*$ ``` I'm trying to validate a string between 0-10 characters, the string cannot contain more the two spaces in a row or cannot be empty. The string cannot contain any special characters and can be case insensitive and can include hyphens. How can I limit input to between 0-10 characters? I tried ``` ^[a-zA-Z0-9]+( [a-zA-Z0-9]+{0,10})*$ ``` but it does not work.