Case Insensitive comparison in C# [duplicate]

Answer 1

Convert both strings to a same case, either upper or lower.

string1.ToUpper().Contains(string2.ToUpper());

Answer 2

You can either convert both strings to uppercase, or use regular expressions:

using System.Text.RegularExpressions;

class Program {
    static void Main(string[] args) {
        string string1 = "TermSomething";
        string string2 = "term";
        bool test1 = string1.ToUpperInvariant().Contains(string2.ToUpperInvariant());
        bool test2 = Regex.IsMatch(string1, Regex.Escape(string2), RegexOptions.IgnoreCase);
    }
}

Note that if you use regular expressions you should escape the search string, so that special regex characters are interpreted literally.

Answer 3

string1.ToUpperInvariant().Contains(string2.ToUpperInvariant());

Answer 4

Regex.IsMatch(string1,string2,RegexOptions.IgnoreCase);

This returns boolean value.....

Answer 5

Why not this:

if (string1.IndexOf(string2, StringComparison.OrdinalIgnoreCase) >= 0)
{  
}

Answer 6

string.Equals("this will return true", "ThIs WiLL ReTurN TRue", StringComparison.CurrentCultureIgnoreCase)

or, for contains

if (string1.IndexOf(string2, StringComparison.CurrentCultureIgnoreCase) >= 0)