CodeBreaker Kata without ifs

WithoutIf.cs

class Rules
    {
        private string passcode;

        public Rules(string passcode)
        {
            this.passcode = passcode;
        }

        internal string Match(string code)
        {
            string correctMatches = GetMatchString(code, "*", (c, i) =>  passcode[i] == c);
            string incorrectMatches = GetMatchString(code, "X", (c, i) => passcode.IndexOf(c) != -1 &&  passcode[i] != c);

            return correctMatches + incorrectMatches;
                
        }

        private string GetMatchString(string code, string resultChar, Func<char, int, bool> criteria)
        {
            int matches = code.Where(criteria).Count();

            return String.Join("", Enumerable.Range(0, matches).Select(x => resultChar));
        }

    }