Regular expression to validate Digit alphabet DigitDigit

rao965 · May 23rd, 2009, 11:42 AM

Hi,

I need a regex to allow the user to insert type in a text box strings that maches this pattern:

DigitAlphabet(upper case)DigitDigit i.e the length of the input must be 4 and it must consist of a number a and alphabet number number for example:

2R67 or 0K98 or 3W77

but not 2r67 or ok98 or 2w77

many thanks for your help

gbianchi · May 23rd, 2009, 12:13 PM

HEllo.. Since there are only 4 chars, isn't faster to just check the char one at a time???

to check if one is uppercase, match the char with the same char.uppercase.

rao965 · May 23rd, 2009, 07:21 PM

Quote:

Originally Posted by gbianchi

HEllo.. Since there are only 4 chars, isn't faster to just check the char one at a time???

to check if one is uppercase, match the char with the same char.uppercase.

Thanks gbianchi for your reply,

If i write a function to check each charector one by one, how can i use it with RegularExpressionValidator control.

If had the regExp I asigned ValidatorExpression to the RegExp pattern.

Thanks

gbianchi · May 23rd, 2009, 07:26 PM

you can't. If you want to use the control you need the reg exp. You never said you need it for the control, So i didn't assume that.

philip_cole · May 23rd, 2009, 08:27 PM

When I'm building regular expressions, I always find the cheat sheet at regexlib.com handy - http://www.regexlib.com/CheatSheet.aspx Also their tester is quite useful - http://www.regexlib.com/RETester.aspx
For your problem you need to match numbers (\d) and upper-case letters ([A-Z]). Also to ensure they only enter 4 characters you want to add start and end markers round it (^ and $). So your expression becomes:

Code:

^\d[A-Z]\d\d$

HTH
Phil

PS. You could use a separate function to do your own check by using a CustomValidator, but it's somewhat overkill to shave off a couple of nanoseconds of processing time

rao965 · May 26th, 2009, 06:11 AM

Hi Philip,

First thanks for your help.
I tried your regex code but the problem is in the css file i have set the text box text uppercase and this casuses the vilidation error message to fire up.

I need to set the textbox text to upper so that the user does not need to press Shift Key.

Any idea how this can be sorted.

Thanks

Quote:

Originally Posted by philip_cole

When I'm building regular expressions, I always find the cheat sheet at regexlib.com handy - http://www.regexlib.com/CheatSheet.aspx Also their tester is quite useful - http://www.regexlib.com/RETester.aspx
For your problem you need to match numbers (\d) and upper-case letters ([A-Z]). Also to ensure they only enter 4 characters you want to add start and end markers round it (^ and $). So your expression becomes:

Code:

^\d[A-Z]\d\d$

HTH
Phil

PS. You could use a separate function to do your own check by using a CustomValidator, but it's somewhat overkill to shave off a couple of nanoseconds of processing time

philip_cole · May 26th, 2009, 06:57 AM

I don't think you can really force it as uppercase, unless you do some javascript like:

Code:

<input type="text" value="" name="thecode" onkeyup="this.value = this.value.toUpperCase()" />

but even that isn't foolproof

If the codes are always going to be uppercase, its probably easier and more reliable, as you aren't forcing the user to enter it correctly, to make the regexp case insenitive and change the value to uppercase in the back end, e.g. in the page code or your database insert.

Phil

rao965 · June 3rd, 2009, 05:32 AM

Hi Phili,

first thanks for your help with this issue.

Now I have added

Code:

<input type="text" value="" name="thecode" onkeyup="this.value = this.value.toUpperCase()" />

into the textbox control but now the regEx does not fire up i.e

any idea?

Thanks
Rao

Quote:

Originally Posted by philip_cole

I don't think you can really force it as uppercase, unless you do some javascript like:

Code:

<input type="text" value="" name="thecode" onkeyup="this.value = this.value.toUpperCase()" />

but even that isn't foolproof

If the codes are always going to be uppercase, its probably easier and more reliable, as you aren't forcing the user to enter it correctly, to make the regexp case insenitive and change the value to uppercase in the back end, e.g. in the page code or your database insert.

Phil