regular validation expression in asp.net

Question

i have got a code to edit some function. There is a text box in that web application. It using a regular expression validator control to validate the text box. the validation expression is

ValidationExpression="[\w]{3,15}"

it accept all letters,numbers and underscores. but it do not accept special characters like \,/ * . i want to change the above regular expression to accept / .

i hope someone can explain what the above regular expression means and how to change that expression to accept / without affecting current regular expression i am using asp.net and c#

Answer 1

string ValidationExpression= "[\w/]{3,15}"

• [...] match a single character presents in the list between brackets
• [...]{3,15} match between 3 and 15 characters presents between brackets
• \w match a word character (letter, digit, underscore...)
• / match the character /

So [\w/]{3,15} match a word character or '/' between 3 and 15 times.

Answer 2

Hi, You current regular expression can be deconstructed as follows :

[] brackets represents regular expression group. Regex engine will try to match all the characters or group of characters given inside [] with the input string.

\w - Allow all the alpha numberic characters which includes upper case and lower case alphabets and 0 to 9 numbers and and underscore (This does not include other special characters like / or # ,etc ).

{3,15} means minimum 3 and maximum 15 alphanumeric characters must be provided in order to successfully match the string.

To add other charters, you need to add them explicitly. If you want to add / your regex should be like [\w/]{3,15}.

You can learn everything about regex here.