How to call waterfall dialog from QnaBot (qna maker api) in C# [Bot Framework v4]?

Question

I have created a qna maker bot in Bot Framework v4 using c#, and now when there are no answers found in qna knowledge base, I have to call a waterfall dialog to ask some questions to the users.

How do I have to do this?

protected override async Task OnMessageActivityAsync(ITurnContext<IMessageActivity> turnContext, CancellationToken cancellationToken)
    {
        var httpClient = _httpClientFactory.CreateClient();

        var qnaMaker = new QnAMaker(new QnAMakerEndpoint
        {
            KnowledgeBaseId = _configuration["QnAKnowledgebaseId"],
            EndpointKey = _configuration["QnAAuthKey"],
            Host = GetHostname()
        },
        null,
        httpClient);

        _logger.LogInformation("Calling QnA Maker");

        // The actual call to the QnA Maker service.
        var response = await qnaMaker.GetAnswersAsync(turnContext);
        if (response != null && response.Length > 0)
        {
            string message = GetMessage(response[0].Answer);
            Attachment attachment = GetHeroCard(response[0].Answer);
            await turnContext.SendActivityAsync(MessageFactory.Text(message), cancellationToken);
            if (attachment != null)
                await turnContext.SendActivityAsync(MessageFactory.Attachment(attachment), cancellationToken);
        }
        else
        {  
            //HERE I WANT TO CALL WATERFALL DIALOG
            //await turnContext.SendActivityAsync(MessageFactory.Text("No QnA Maker answers were found."), cancellationToken);
        }
    }

ranusharao ranusharao · Accepted Answer · 2019-09-04T08:17:36

You can make use of a multi-turn prompt, which uses a waterfall dialog, a few prompts, and a component dialog to create a simple interaction that asks the user a series of questions.The bot interacts with the user via UserProfileDialog. When we create the bot's DialogBot class, we will set the UserProfileDialog as its main dialog. The bot then uses a Run helper method to access the dialog.

To use a prompt, call it from a step in your dialog and retrieve the prompt result in the following step using stepContext.Result. You should always return a non-null DialogTurnResult from a waterfall step.

An example of asking the user for their name is as follows:

 public class UserProfileDialog : ComponentDialog
    {
        private readonly IStatePropertyAccessor<UserProfile> _userProfileAccessor;

        public UserProfileDialog(UserState userState)
            : base(nameof(UserProfileDialog))
        {
            _userProfileAccessor = userState.CreateProperty<UserProfile>("UserProfile");

            // This array defines how the Waterfall will execute.
            var waterfallSteps = new WaterfallStep[]
            {
                NameStepAsync,
                NameConfirmStepAsync,
                SummaryStepAsync,
            };

            // Add named dialogs to the DialogSet. These names are saved in the dialog state.
            AddDialog(new WaterfallDialog(nameof(WaterfallDialog), waterfallSteps));
            AddDialog(new TextPrompt(nameof(TextPrompt)));
            AddDialog(new ConfirmPrompt(nameof(ConfirmPrompt)));

            // The initial child Dialog to run.
            InitialDialogId = nameof(WaterfallDialog);
        }

        private static async Task<DialogTurnResult> NameStepAsync(WaterfallStepContext stepContext, CancellationToken cancellationToken)
        {
            stepContext.Values["transport"] = ((FoundChoice)stepContext.Result).Value;

            return await stepContext.PromptAsync(nameof(TextPrompt), new PromptOptions { Prompt = MessageFactory.Text("Please enter your name.") }, cancellationToken);
        }

        private async Task<DialogTurnResult> NameConfirmStepAsync(WaterfallStepContext stepContext, CancellationToken cancellationToken)
        {
            stepContext.Values["name"] = (string)stepContext.Result;

            // We can send messages to the user at any point in the WaterfallStep.
            await stepContext.Context.SendActivityAsync(MessageFactory.Text($"Thanks {stepContext.Result}."), cancellationToken);

            // WaterfallStep always finishes with the end of the Waterfall or with another dialog; here it is a Prompt Dialog.
            return await stepContext.PromptAsync(nameof(ConfirmPrompt), new PromptOptions { Prompt = MessageFactory.Text("Would you like to give your age?") }, cancellationToken);
        }


        private async Task<DialogTurnResult> SummaryStepAsync(WaterfallStepContext stepContext, CancellationToken cancellationToken)
        {
            if ((bool)stepContext.Result)
            {
                // Get the current profile object from user state.
                var userProfile = await _userProfileAccessor.GetAsync(stepContext.Context, () => new UserProfile(), cancellationToken);

                userProfile.Name = (string)stepContext.Values["name"];

            }
            else
            {
                await stepContext.Context.SendActivityAsync(MessageFactory.Text("Thanks. Your profile will not be kept."), cancellationToken);
            }

            // WaterfallStep always finishes with the end of the Waterfall or with another dialog, here it is the end.
            return await stepContext.EndDialogAsync(cancellationToken: cancellationToken);
        }      
    }

This documentation will help you get a better understanding of multi prompt dialogs.

Hope this helps.

How to call waterfall dialog from QnaBot (qna maker api) in C# [Bot Framework v4]?

1 Answers