RegularExpressionValidator

Hi there.

I want to allow the user to select any but a couple of items in a listbox. I've got a RegularExpressionValidator for the listbox but I'm somewhat stuck on the regular expression - how do I say NOT string a or b?
"^(a|b)$" is exactly wrong but I don't seem to be able to say NOT "^(a|b)$" ... any clues???

Thanks for your time,
T

If you need to match any one-character string , except "A" AND "B", try

Code:

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^[^AB]$

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If you need to match any string not containing the letters 'A' or 'B', try

Code:

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[^AB]

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Or if you need to match any string not beginning with the letter 'A' or 'B':

Code:

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^[^AB]

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- petter

Thanks for the reply. I'm trying to match a string, rather than character set - for example NOT ("Apples" OR "Pears"):
NOT (and that's the bit I'm having trouble with) "^(Apples|Pears)$".

Thanks again,
T

Ok, then you can use negative lookahead.

To match a string, except "Apples" or "Pears":

Code:

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^(?!Apples$|Pears$).*$

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Or, to match any string except thoes begginning with "Apples" or "Pears", try:

Code:

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^(?!Apples|Pears).*$

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- petter

That's exactly it - you're brilliant and amazing. I wasn't even on the right track! Regular expressions are indeed a world unto their own...

Thanks again,
T.