public static Task <bool> OrderNumberValidator(PromptValidatorContext <string> promptContext, CancellationToken cancellationToken) { // check regex - 7 digit number placeholder var regex = new Regex(@"\d{7}", RegexOptions.IgnoreCase); var match = regex.Match(promptContext.Recognized.Value); if (match.Success) { var id = promptContext.Recognized.Value = match.Value; // lookup order number to verify it exists var order = _client.GetOrderByNumber(id); // add to state if (order != null) { return(Task.FromResult(true)); } } return(Task.FromResult(false)); }