How can I ignore case in a regex?

Question

I have an ASP.NET RegularExpressionValidator that checks file extensions. Is there a quick way I can tell it to ignore the case of the extension without having to explicitly add the upper case variants to my validation expression?

ValidationExpression="([^.]+[.](jpg|jpeg|gif|png|wpf|doc|docx|xls|xlsx ...

You can get rid of some of the duplication in that regex: `(jpe?g|gif|png|wpf|docx?|xlsx? ...` — PEZ, Jan 11 '09 at 13:14

score 24 · Accepted Answer · edited Aug 12 '13 at 04:25

24

Server-side, "(?i)" can be used, but this doesn't work client-side. See here for more discussion and workaround.

i.e. "...(?i)(jpg|jpeg|gif|png|wpf|..."

edited Aug 12 '13 at 04:25

Paul

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answered Jan 11 '09 at 13:07

Marc Gravell

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I can't reach that link. I actually get an 403.6... should I get worried? – PEZ Jan 11 '09 at 13:15
@PEZ: retried, works fine... but there are plenty of others - just search +RegularExpressionValidator +IgnoreCase – Marc Gravell Jan 11 '09 at 13:17
I've tried that myself already. Doesn't help. It seems the server really has a problem with my IP! – PEZ Jan 11 '09 at 13:23
The link in this answer is broken now. If someone has a good link to replace it with, please do so! – Highly Irregular Dec 13 '11 at 04:35

score 2 · Answer 2 · answered Jan 11 '09 at 13:11

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In VisualBasic.NET, you can use the RegExOptions to ignore he case:

Dim RegexObj As New Regex("([^.]+[.](jpg|jpeg|gif))", RegexOptions.IgnoreCase)

answered Jan 11 '09 at 13:11

Sebastian Dietz

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Yes, sorry, saw it too late. I should read the questions more carefully. – Sebastian Dietz Jan 11 '09 at 13:25

score 1 · Answer 3 · answered Jan 11 '09 at 13:13

1

According to the Regular Expression Options, this should work:

// Added LowerCase i:
ValidationExpression="(?i:[^.]+[.](jpg|jpeg|gif|png|wpf|doc|docx|xls|xlsx ...

answered Jan 11 '09 at 13:13

Michael Stum

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as long as it is server-side; I don't think it works client-side – Marc Gravell Jan 11 '09 at 13:16

How can I ignore case in a regex?

3 Answers3