Problem with Regex in .NET (C#)

Posted by Craig Bovis on Stack Overflow See other posts from Stack Overflow or by Craig Bovis
Published on 2010-05-05T11:52:31Z Indexed on 2010/05/05 12:08 UTC
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c#

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.NET

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regex

I'm trying to write a a regex to validate a string to match the following rules.

Must start with a-z (case insensitive)
Must only contain a-z A-Z 0-9 . -

I've put something together based on my limited knowledge and ran it through an online testing tool for a whole bunch of situations and the results were as I had hoped however when I place the pattern into my .NET code it doesn't match correctly.

The pattern I am using is,

[a-zA-Z][a-zA-Z0-9.\-]*

Is this the correct pattern or am I barking up the wrong tree?

Some examples of what I'm expecting.

craig.bovis - VALID
24craig - INVALID
craig@bovis - INVALID
craig24 - VALID
-craig24 - INVALID
craig24.bovis-test - VALID

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