c# - Regex to validate length of alphanumeric string -

i have following regular expression:

^[a-za-z0-9]+( [a-za-z0-9]+)*$ 

i'm trying validate string between 0-10 characters, string cannot contain more 2 spaces in row or cannot empty. string cannot contain special characters , can case insensitive , can include hyphens.

how can limit input between 0-10 characters?

i tried

^[a-za-z0-9]+( [a-za-z0-9]+{0,10})*$ 

but not work.

i this:

^(?!.*  )(?=.*[\w-])[\w -]{1,10}$ 

this uses negative look-ahead (?!.* ) assert there not 2 consecutive spaces, , positive look-ahead (?=.*[\w-]) assert has @ least 1 non-space character (i assume "empty" means "only spaces").

note if can't "empty", can't 0 length, length range must 1-10, not 0-10.

of tiny note fact don't need escape dash in character class if it's first or last character.