Example. The RegexOptions enum is a Regex argument. This example shows how RegexOptions.IgnoreCase affects the result of the IsMatch method on an input that is in a different case.
Note When IgnoreCase is specified, the match succeeds. Otherwise it fails. IgnoreCase will relax the regular expression.
using System;
using System.Text.RegularExpressions;
class Program
{
static void Main()
{
// The input string has an uppercase trailing letter.
const string value = "carroT";
// Print result of IsMatch method:
// ... With IgnoreCase;
// ... And without any options set.
Console.WriteLine(Regex.IsMatch(value, "carrot", RegexOptions.IgnoreCase));
Console.WriteLine(Regex.IsMatch(value, "carrot"));
}
}True
False
Other methods. You can use RegexOptions.IgnoreCase with other methods, not just IsMatch. Try it with Split, Matches and Match. It has the same effect when used with these methods.
A summary. RegexOptions.IgnoreCase will relax the requirements for an input with letters to be matched. Thus, the input string can have a capital or lowercase letter.
A final note. The RegexOptions.IgnoreCase argument is useful in many regular expressions. Before using ToLower(), consider using IgnoreCase.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.