Regular Expression validations in .net

Experts,

I have a problem..I need to allow following characters (  space, hyphen -, forward slash /, back slash\, apostrophe'   ) in my textbox and validations has to pass. I achieved through regular expressions. Whether these special characters occurs single time or multiple times.

<RegularExpressionValidator ValidationExpression="^([a-zA-Z0-9,\#])*([a-zA-Z0-9,\-\.\s\#\|\'\\])*$" ErrorMessageID="Validate.MyProfile.Address1.ValidCharacters" />

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However, the problem is..I have to allow all these characters only one time in the textbox. Multiple occurences are NOT allowed in the future. Please help me fix this problem.

Thanks
SubbuUSAAsked:
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Carl BohmanConnect With a Mentor Commented:
It sounds like you can have multiple special characters in a single cluster with no other clusters of special characters and no duplicate special characters in that cluster.  If so, this should work:
<RegularExpressionValidator ValidationExpression="^[a-zA-Z0-9,\#]*(?!([\-\.\s\|\'\\]).*\1)[\-\.\s\|\'\\]*[a-zA-Z0-9,\#]*$" ErrorMessageID="Validate.MyProfile.Address1.ValidCharacters" />

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If, however, multiple clusters of special characters are allowed, then this is the regex to use:
<RegularExpressionValidator ValidationExpression="^(?!.*([\-\.\s\|\'\\]).*\1)[a-zA-Z0-9,\#]*(?:[\-\.\s\|\'\\][a-zA-Z0-9,\#]*)*$" ErrorMessageID="Validate.MyProfile.Address1.ValidCharacters" />

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Frank WhiteCommented:
Hmm. If I understand this correctly, isn't it as simple as declaring a boolean variable and adding a regexp search for your validated characters? If the added regexp finds a match, set the bool to true, and then add a check for that bool before the validation. If false, do the above validation, else, do another validation that rejects those characters. If needed, save the bool to some file or registry entry.

Or am I misunderstanding the problem?
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SubbuUSAAuthor Commented:
@ DaFranker

Existing architecuture validates only through xml files having regular expressions for some reasons. No code behind is allowed in my architecture to validate.

Is there a way,  I can fix this by writing a regex code like the one which I have provided that do this restriction? Any help would be appreciated
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Carl BohmanCommented:
Is it that you can only allow one of those characters once or that you can allow each of them once?  For example, if a string contained both a string and a hyphen, would it be considered valid or invalid?

This seems like an odd validation requirement.  Is it for a school assignment?
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Carl BohmanCommented:
Correction: ...both a space and a hyphen...
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käµfm³d 👽Connect With a Mentor Commented:
If I understand you issue correctly, try:

<RegularExpressionValidator ValidationExpression="^([a-zA-Z0-9,#])*([a-zA-Z0-9,.#|]| (?![^ ]* )|-(?![^-]*-)|/(?![^/]*/)|\\(?![^\\]*\\)*$" ErrorMessageID="Validate.MyProfile.Address1.ValidCharacters" />

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SubbuUSAAuthor Commented:
@bounsy

Thanks for your reply.

" Is it that you can only allow one of those characters once?"

The string containing a space and hyphen is considered as valid. The combination of special characters are also valid but it can appear only once. They can be in any order but can occur only once.

No it is not for school..it is for banks
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SubbuUSAConnect With a Mentor Author Commented:
@kaufmed
Your code does not fire any validation messages to me. May be something is wrong..could not find what is causing that.

@bounsy

I do not understand what do you mean by clusters but your code did not work for me.

I tried using your first line of code..it does not allow me even type hyphen , slash one time..it throws up the error message..

I am supposed to allow space, hyphen, slashes both, apostrophe one time in the textbox and show throw if it occurs more than one time. regardless of what sequence the characters and special characters may appear. it does not matter.


Your second line of code fixes my problem. Thanks again for helping me.
thanks
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SubbuUSAAuthor Commented:
Thanks Kaumed and Bounsy for saving my day..you have a great day
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