Hi,

I've been trying to write a very simple Regular Expression for a password textbox, which consists of restricting the password length to between 4 and 20 characters, and having no whitespace.

However, I can't find any easy way of doing this (I would like to have the whitespaces checked within the Regular Expression rather than using another method.

Is there an easy way of doing this?  I have tried using the [^\s] character class along with \w{4,20} but it doesn't work,

Thanks for your time,

John

^(?=.*[a-zA-Z].*[a-zA-Z])(?=.*\d.*\d)[a-zA-Z0-9]{5,20}$

Description: Password matching expression. Password must consists of at least 5 characters and not more than 20 characters. Password must contain only letters and digits. Password must contain at least 2 digits and at least 2 letters.

Also, try www.regexlib.com

Enter "password" as search criteria and you will get more examples.

Just wondering why is it wrong to contain space in the password field?

The only concern is you don't know if .net will try to trim it when the space occurs on either end of the string.

Check below expression

^[a-zA-Z0-9]{4,20}

HC

Haissam:

^[a-zA-Z0-9]{4,20}

Looks like how I would go, but you forgot the dollar on the end to force match start to finish.

^[a-zA-Z0-9]{4,20}$

I'm in error.

Why would you want to restrict your users from using special characters etc?

Surely all you want is to enforce a minium requirement, not restrict the password complexity. I agree with the earlier comment about the spaces also.

Hi,

Thanks for your replies, it is much appreciated.

Bullpit, the example and link is great, thanks for your help,

John