Validate Email Address

        /// <summary>
        /// Validates an Email Address.
        /// </summary>
        /// <param name="emailAddress">The email address.</param>
        /// <returns>True if the specified string is valid email address,
        /// other wise false.</returns>
        /// <remarks>
        /// Will match only syntactically correct Email Addresses.
        /// Dose not validate an IPv6 Domain part.
        /// Validation rules and samples taken from here:
        /// http://en.wikipedia.org/wiki/Email_address#Invalid_email_addresses
        /// </remarks>
        public static bool IsValidEmailAddress(string emailAddress)
        {
            return !string.IsNullOrWhiteSpace(emailAddress)
                && Regex.IsMatch(emailAddress, @"^(?:(?:[\w`~!#$%^&*\-=+;:{}'|,?\/]+(?:(?:\.(?:""(?:\\?[\w`~!#$%^&*\-=+;:{}'|,?\/\.()<>\[\] @]|\\""|\\\\)*""|[\w`~!#$%^&*\-=+;:{}'|,?\/]+))*\.[\w`~!#$%^&*\-=+;:{}'|,?\/]+)?)|(?:""(?:\\?[\w`~!#$%^&*\-=+;:{}'|,?\/\.()<>\[\] @]|\\""|\\\\)+""))@(?:[a-zA-Z\d\-]+(?:\.[a-zA-Z\d\-]+)*|\[\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\])$");
        }