EmailAddressValidator.cs

public static class EmailAddressValidator
{
    public const string EmailAddressRegex = "^[^@]+@[a-zA-Z0-9_-]+(\\.[a-zA-Z0-9_-]+)+$";
    private static readonly Regex Validator = new Regex(EmailAddressRegex);

    public static bool IsValid(string email)
    {
        return email != null && !email.Contains("\n") && Validator.Match(email).Success;
    }
}