Re:Usename regex
Hello Mick,
Quote
Hi All,
I would like to know how I can limit users to only registering
usernames
which have alphanumberic characters and one underscore.
From what I understand is I can use a regex to do this. But I have no
idea how to do it. I have only used a customfieldvalidor before. And
the
reason I cant do it now is because of the design of the page itself.
So basically I need to know how, upon a button click, I can compare
the text entered in a textbox, to a regex, if its invalid throw a
error, if its valid proceed.
Thanks.
You can indeed use Regex for this. It's actually a simple expression:
because a regex describes the input from left to right you need to account
for all possible locations of the single '_' you're allowing.
It would be even simpler to just allow underscores as a rule.
The expression comes down to this:
^(_[a-zA-Z0-9]+|[a-zA-Z0-9]+_?|[a-zA-Z0-9]+_[a-zA-Z0-9]+)$
^ First make sure we're matching from the beginning of the input.
( We have multiple options
_[a-zA-Z0-9]+ first find the underscore, followed by an unlimited number
of alphanumeric characters
| OR....
[a-zA-Z0-9]+_? find an unlimited number of alphanumeric characters followed
by an optional underscore
| OR....
[a-zA-Z0-9]+_[a-zA-Z0-9]+ find an unlimited numner of alphanumeric
characters followed by an underscore, followed by more characters.
) No more options
$ End of the string.
Now add a Regex validator to your page. Set the expression to the expression
above and the control to validate to your textbox and you're all done.
Jesse
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