Regex pattern for catching Alphanumeric and underscore only

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ASP.NET

Plese tell me the code for regular expression which allows only:
- numbers
- alphabets
- underscore

Posted 7-Aug-13 22:24pm

16Sonali

Updated 7-Aug-13 23:16pm

Joezer BH

v3

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Dholakiya Ankit · Accepted Answer · 2013-08-07T22:36:00

Solution 1

try this one

HTML

"^[a-zA-Z0-9_]*$"

you can find link below

http://stackoverflow.com/questions/336210/regular-expression-for-alphanumeric-and-underscores[^]

regards...:)

Posted 7-Aug-13 22:36pm

Dholakiya Ankit

Updated 7-Aug-13 23:53pm

v2

Comments

16Sonali 8-Aug-13 4:40am

Thanks a lot!!!!

Joezer BH 8-Aug-13 4:42am

The above regex needs some fixes to suit your question...
e.g. it will also catch spaces, and it will not catch lowercase chars (unless he uses IgnoreCase), see my optional solution

Dholakiya Ankit 8-Aug-13 4:50am

welcome

Joezer BH 8-Aug-13 5:11am

Why don't you fix your regex Ankit?
Your post is as it is, is misleading - Did you read my post above?

Dholakiya Ankit 8-Aug-13 5:44am

actually i was about to change but she have accepted it means she get it and she must have tested it thats why i dont change it maimonides

Joezer BH 8-Aug-13 5:49am

This is a gravely wrong approach! first of all bugs may come up later in the life of the application in which case it will be much harder to find.
Second, anyone else who may look at a post with wrong answers and will use the code in their application only to discover that it has flaws, greatly reduces the reputation of CodeProject.

So leaving a wrong answer is being careless!

Dholakiya Ankit 8-Aug-13 6:04am

i am changing it because of your second reason of codeproject although she have to check it and feed back me first

Joezer BH 8-Aug-13 6:50am

You got my 5 now!

Dholakiya Ankit 8-Aug-13 6:52am

thanks..!! maimonides

Joezer BH 8-Aug-13 7:33am

You are welcome!

Dholakiya Ankit 8-Aug-13 5:50am

ok get it improving it

**Joezer BH** · Accepted Answer · 2013-08-07T22:40:00

Solution 2

C#

string pattern = "^[a-zA-Z0-9_]*$";

See Regex Quick Reference[^]
Learn Regular Expressions (RegEx) with Ease[^]

Posted 7-Aug-13 22:40pm

Joezer BH

Tejas B Pancholi · Accepted Answer · 2013-08-07T23:22:00

Solution 3

For unlimited alpha numeric and numeric and underscore you can enter
Reg exp = "/^[A-Za-z0-9_]*$/";
or
For specific length alpha numeric and numeric and underscore you can enter
Reg exp = "/^[A-Za-z0-9_]{min length,max length}$/";

Posted 7-Aug-13 23:22pm

Tejas B Pancholi

Comments

16Sonali 12-Aug-13 2:24am

Hi,
When I enter special character in textbox in gridview it wont allow but when clicks on cancel button giving below erro......

Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 500

16Sonali 12-Aug-13 2:36am

when clicks on cancel button..it is not cancelled....validation fires for special character...but grid should be in default position......