Checking for Whitespace in FluentValidation

Question

I'm using FluentValidation and trying to create a rule that throws error if there is any whitespace in the string, i.e. for a username.

I've reviewed these SOs, but doesn't seem to work, I'm sure my syntax is off just a little?

What is the Regular Expression For "Not Whitespace and Not a hyphen" and What is the Regular Expression For "Not Whitespace and Not a hyphen"

RuleFor(m => m.UserName).NotEmpty().Length(3, 15).Matches(@"/^\S\z/");

or

RuleFor(m => m.UserName).NotEmpty().Length(3, 15).Matches(@"[^\s]");

Neither of these seem to work. Other rules are not empty and between 3 and 15 characters.

Steck

Answer 1

Just modifying your original rule a bit
edit Ok, removing delimiters as suggested.

RuleFor(m => m.UserName).NotEmpty().Length(3, 15).Matches(@"\A\S+\z");

All it does is force there to be non-whitespace in the whole string from start to finish.

Alternatively, I guess you could combine them into 1 match as in

RuleFor(m => m.UserName).Matches(@"\A\S{3,15}\z");

Galah

This works, except for the / and \ surrounding the expression. Remove those and either works. If you want to update the answer, I can mark it complete. Thanks! RuleFor(m => m.UserName).NotEmpty().Matches(@"\A\S{3,15}\z"); – Steck

RuleFor(m => m.UserName).NotEmpty().Matches(@"\A\S{3,15}\z"); not worked for me. It is showing validating even also when i am entering any characters – Virology

@AnmolRathod - RuleFor(m => m.UserName).NotEmpty().Matches(@"\A\S{3,15}\z"); not worked for me. It is showing validating even also when i am entering any characters This -> \A is absolute beginning of the string. \z is absolute end of string \S{3,15} is 3 to 15 any character except whitespace. And there you have it .. – Galah

@sln what would be final regex than ? – Virology

@AnmolRathod - The final regex was posted March 14, 2014. – Galah

Answer 2

Try the char.IsWhiteSpace

RuleFor(m => m.UserName).NotEmpty().Length(3, 15).Must(userName => !userName.All(c => char.IsWhiteSpace(c)))

Carbonado

Was not able to get this to work. Also might there be a performance if using LINQ to check every character vs. the Regex approach. – Steck

Answer 3

This worked for me with FluentValidation.MVC5 6.4.0

RuleFor(x => x.username).Must(u => !u.Any(x => Char.IsWhiteSpace(x)));

Prothorax

Answer 4

Try this:

RuleFor(m => m.UserName).NotEmpty().Length(3, 15).Must (u => !string.IsNullOrWhiteSpace(u));

Panpsychist

That doesn't work. I'm still able to put whitespace. – Prothorax

Answer 5

 public static string RemoveWhitespace(this string input)
 {
    return new string(input.ToCharArray()
        .Where(c => !Char.IsWhiteSpace(c))
        .ToArray());
 }

RuleFor(x => x.Username).Must(s => s.Length == s.RemoveWhitespace().Length);

Spoofery