Regex to Exclude Double spaces

Question

I am looking for a regular expression for c# asp.net 3.5 that will fail if there are ever any double spaces in a sentence or group of words.

the cat chased the dog = true
the  cat  chased  the dog = false (doubles spaces occur at random intervals)

thanks

Answer 1

Try

^((?!\s{2}).)*$

In this expression (?!\s{2}). matches every character except whitespace ones, followed by another whitespace.