I have an aspx:memo control in asp.net page. The control has a regular expression validator. If the text inserted in the memo is different than the regular expression then the validator triggers an error. So I would like to accept every character except these:
1) -- (double hyphen)
2) // (double slash)
3) ' (Single quote)
4) \\ (double backslash)
5) ^ (Caret)
6) ; (Semicolon)
So far I have created this expression:
^[\na-zA-Z0-9 .,~?`~!@():#&%=+΄<>\\\-\/_"\]\[\}\{]*$
I have put inside every character that I accept in the memo. So the issue is that with this expression I accept slashes and backslashes or hyphens even if they are single or more. How can I disallow the double slashes or hyphens but allow single ones.
I have already lost a lot of time for this. Your help would be greatly appreciated.
Thank you in advance.
^((?!--|\/\/|'|\\\\|\^|;).|\w)*$
(?! ) being the negative look ahead meaning that anything within (separated by |) will cause the validation to fail
\/\/being//with escaped characters
\\\\being\\with escaped characters
. allows any character (except whitespace)
\w allows whitespace