CODEWITHSUNDEEP
c#regexc#-4.0
Kiran Desai
Kiran Desai

Reputation: 1891

Regex for decimal number validation in C#

I need regular expression which allows positive as well as negative range decimals values

like .89, -1000, 0.00, 0, 300, .....

My regex is ^\d*\.?\d*

Problem is that when you entered special characters like $, !, * then it accepts those characters.

Upvotes: 0

Views: 9185

Answers (3)

Jules
Jules

Reputation: 587

You missed a backslash! A single dot has a different meaning in Regex expressions.

public static bool IsValidDecimal()
{
    string input = "132456789"
    Match m = Regex.Match(input, @"^-?\d*\.?\d+");
    return m.Success && m.Value != "";
}

Upvotes: 1

CinCout
CinCout

Reputation: 9619

If you are keen on using regex, the following will do:

^-?[0-9]*\.?[0-9]+$

See live demo

Upvotes: 2

Soner Gönül
Soner Gönül

Reputation: 98740

Instead of regex, I would parse it with decimal.Parse with AllowDecimalPoint and AllowLeadingSign styles and a culture that has . as a NumberDecimalSeparator like InvariantCulture.

var d = decimal.Parse("-.89", 
                      NumberStyles.AllowDecimalPoint | NumberStyles.AllowLeadingSign, 
                      CultureInfo.InvariantCulture);

This captures all needs you mentioned.

Upvotes: 1

Related Questions