String Equals Ignore Case

        public static bool EqualsIgnoreCase(this string a, string b)
        {
            if (a == null && b == null)
                return true;
            if (a != null && b == null)
                return false;
            if (a == null && b != null)
                return false;
            return string.Equals(a, b, StringComparison.InvariantCultureIgnoreCase);
        }