Question

I want to validate Winforms text box with regex.

The input sting example:

ZX1 OR N?V OR 2L? OR ?55 (any sequence of three symbols length strings with OR between them)

What is the regex that you would advise?

UPDATE:
Trying this one but seams to be it is not 100% correct

string text = "ZX1 OR N?V OR 2L? OR ?55";
Regex r = new Regex("([0-9A-Z?]{3} OR )*[0-9A-Z?]{3}");

Answer 1

"^\\s*\\S{3}(?:\\s+OR\\s+\\S{3})*\\s*$"

should work in a variety of languages.

\\S

matches any non-space character, and

\\s

matches any space character, so the regex above matches any number of triplets of non-space characters separated by the string "OR" surrounded by space characters.

The ^ and $ serve to ensure that it matches the whole string so you can take those out if you want to find this pattern inside a larger string.