public static class Program
public static void Main(string[] args)
var source = "TaxIdentificationNumber";
var check = "TaxIdentificationNumb";
var str = StringComparison.CurrentCultureIgnoreCase;
Console.WriteLine(Contains(source, check, str));
public static bool Contains(this string source, string toCheck, StringComparison comp)
return source.IndexOf(toCheck, comp) >= 0;