Regular expression to match numbers only not starting with zero

Question

I have a textbox on the form and I want the user to be able to enter only numbers, and first number can not be zero. Which pattern must be in this case?

windows form or webform? for webform Aliostad got the answer for windows overload the onkeypress event an chech the key pressed for values if it's windows form i'll provide the code — Radu, Apr 14 '11 at 10:21

Aliostad · Accepted Answer · 2011-04-14T10:23:26.043

12

Use this expression

string expression = @"^[1-9]\d*$";

For anyone wanting to test the expression, use this link: http://www.rubular.com/r/1JIPP8E1zH

edited Apr 14 '11 at 10:23

answered Apr 14 '11 at 10:05

Aliostad

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But it doesnt allow for eaxample 10000 number – namco Apr 14 '11 at 10:16
@Namco, why?? Of course it does... Have a look here http://www.rubular.com/r/1JIPP8E1zH – Aliostad Apr 14 '11 at 10:24
oh..great i love this site.rubular..this – Lijo Jul 06 '14 at 20:10

score 1 · Answer 2 · answered Apr 14 '11 at 10:06

1

Try with:

/^[1-9][0-9]*$/

What length of string you accept ?

If you allow empty string too try with:

/^([1-9][0-9]*)?$/

answered Apr 14 '11 at 10:06

hsz

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If the max length of the number is 10. then? – Bhuvan Jun 06 '13 at 05:34

score 1 · Answer 3 · answered Apr 14 '11 at 10:09

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Alternatively, and I would suggest this for localization purposes, consider

 double.Parse(myTextBox.Text, System.Globalization.CultureInfo.CurrentCulture);

as alternative. It parses numbers with decimals or whatever variation you like according to the settings (culture) which is installed. In my country, with a dot as decimals seperator.

answered Apr 14 '11 at 10:09

Jaapjan

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Nice alternative, just to note `TryParse` might be more useful, depending. – Grant Thomas Apr 14 '11 at 10:35

Regular expression to match numbers only not starting with zero

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