/// <summary>
        /// Check if property is in list values.
        /// </summary>
        /// <param name="values">List of values.</param>
        /// <param name="comparer">An optionnal equality comparer to compare value.</param>
        /// <returns>Current instance.</returns>
        public PropertyValidator <TRow> IsStringValues(string[] values, IEqualityComparer <string> comparer = null)
        {
            StringRule <TRow> method = new StringRule <TRow>((x) => this.getter(x));

            method.IsStringValues(values, comparer);
            this.validationRules.Add(method);
            return(this);
        }