I need a regex that will accept only digits from 0-9 and nothing else. No letters, no characters.
I thought this would work:
^[0-9]
or even
\d+
but these are accepting the characters : ^,$,(,), etc
I thought that both the regexes above would do the trick and I'm not sure why its accepting those characters.
EDIT:
This is exactly what I am doing:
private void OnTextChanged(object sender, EventArgs e)
{
if (!System.Text.RegularExpressions.Regex.IsMatch("^[0-9]", textbox.Text))
{
textbox.Text = string.Empty;
}
}
This is allowing the characters I mentioned above.
Your regex ^[0-9] matches anything beginning with a digit, including strings like "1A". To avoid a partial match, append a $ to the end:
^[0-9]*$
This accepts any number of digits, including none. To accept one or more digits, change the * to +. To accept exactly one digit, just remove the *.
UPDATE: You mixed up the arguments to IsMatch. The pattern should be the second argument, not the first:
if (!System.Text.RegularExpressions.Regex.IsMatch(textbox.Text, "^[0-9]*$"))
CAUTION: In JavaScript, \d is equivalent to [0-9], but in .NET, \d by default matches any Unicode decimal digit, including exotic fare like ? (Myanmar 2) and ? (N'Ko 9). Unless your app is prepared to deal with these characters, stick with [0-9] (or supply the RegexOptions.ECMAScript flag).
Source: Stackoverflow.com