Bot framework v4.0 how to execute the previous waterfall step in a dialog

Question

I'm trying to create a dialog in which I define multiple waterfall steps. In the context of this dialog, I need sometimes to go back to the previous waterfall step according to the choice of the user. I found this method :

 await stepContext.ReplaceDialogAsync("Name of the dialog");

however, this method re-execute the whole dialog and this is not what I need.

In fact, the waterfall steps that I created are three :

• ChoiceCallStepAsync: The first step will list the first 10 calls of the user with the options to show older steps
• ShowCallStepAsync: The second step will show the call that the user choose or go back to the first step if the user clicked on "show older"
• EndDialog: The third step will terminate the dialog

My code is :

public class ListAllCallsDialog : ComponentDialog
    {

        // Dialog IDs
        private const string ProfileDialog = "ListAllCallsDialog";



        /// <summary>
        /// Initializes a new instance of the <see cref="ListAllCallsDialog"/> class.
        /// </summary>
        /// <param name="loggerFactory">The <see cref="ILoggerFactory"/> that enables logging and tracing.</param>
        public ListAllCallsDialog(ILoggerFactory loggerFactory)
            : base(nameof(ListAllCallsDialog))
        {
            // Add control flow dialogs
            var waterfallSteps = new WaterfallStep[]
            {
                   ListAllCallsDialogSteps.ChoiceCallStepAsync,
                   ListAllCallsDialogSteps.ShowCallStepAsync,
                   ListAllCallsDialogSteps.EndDialog,
            };
            AddDialog(new WaterfallDialog(ProfileDialog, waterfallSteps));
            AddDialog(new ChoicePrompt("cardPrompt"));
        }

        /// <summary>
        /// Contains the waterfall dialog steps for the main dialog.
        /// </summary>
        private static class ListAllCallsDialogSteps
        {
            static int callListDepth = 0;
            static List<string> Calls;
            public static async Task<DialogTurnResult> ChoiceCallStepAsync(WaterfallStepContext stepContext, CancellationToken cancellationToken)
            {
                await stepContext.Context.SendActivityAsync(
                   "Right now i'm in list all calls dialog",
                   cancellationToken: cancellationToken);
                GetAllCalls();
                return await stepContext.PromptAsync("cardPrompt", GenerateOptions(stepContext.Context.Activity, callListDepth), cancellationToken);
            }

            public static async Task<DialogTurnResult> ShowCallStepAsync(WaterfallStepContext stepContext, CancellationToken cancellationToken)
            {
                // Get the text from the activity to use to show the correct card
                var text = stepContext.Context.Activity.Text.ToLowerInvariant();
                if(text == "Show older")
                    //Go back to the first step
                else if(text == "Show earlier")
                    //Go back to the first step
                else
                    await stepContext.Context.SendActivityAsync(
                   "The call you choose is : " + text.ToString(),
                   cancellationToken: cancellationToken);
                   return await stepContext.ContinueDialogAsync();

            }

            public static async Task<DialogTurnResult> EndDialog(WaterfallStepContext stepContext, CancellationToken cancellationToken)
            {
                await stepContext.Context.SendActivityAsync(
               "Getting back to the parent Dialog",
               cancellationToken: cancellationToken);
                return await stepContext.EndDialogAsync(null, cancellationToken);
            }

            /// <summary>
            /// Creates options for a <see cref="ChoicePrompt"/> so the user may select an option.
            /// </summary>
            /// <param name="activity">The message activity the bot received.</param>
            /// <returns>A <see cref="PromptOptions"/> to be used in a prompt.</returns>
            /// <remarks>Related type <see cref="Choice"/>.</remarks>
            private static PromptOptions GenerateOptions(Activity activity, int callListDepth)
            {
                // Create options for the prompt
                var options = new PromptOptions()
                {
                    Prompt = activity.CreateReply("Please choose a call from the list below"),
                    Choices = new List<Choice>(),
                };


                for(int i=10*callListDepth; i <= 10 * (callListDepth + 1); i++)
                {
                    if (Calls.ElementAtOrDefault(i) != null)
                      options.Choices.Add(new Choice() { Value = Calls[i] });

                }
                options.Choices.Add(new Choice() { Value = "Show older" });
                if(callListDepth!=0)
                    options.Choices.Add(new Choice() { Value = "Show earlier" });
                return options;
            }
            private static void GetAllCalls()
            {

                //List of all calls found
                for (int i = 0; i < 30; i++)
                  Calls.Add("Call" + i.ToString());
            }

        }

}

Can someone show me how to do this, please ?

Answer 1

You can use the option parameter in the method "ReplaceDialogAsync" and skip steps with the method "NextAsync".

For example in my waterfall steps (defined in the constructor):

        AddDialog(new WaterfallDialog(nameof(WaterfallDialog), new WaterfallStep[]
        {
            IntroStepAsync,
            ActStepAsync,
            FinalStepAsync
        }));

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

If you want pass to second step (in my case ActStepAsync) from the final step (FinalStepAsync) , when I going to replace the dialog I use the created a label in the Dialog:

private const string FLAG = "MY_FLAG";

When I invoke the method from final step I do this :

return await stepContext.ReplaceDialogAsync(InitialDialogId, FLAG, cancellationToken);

So I only need check the option in the first step if the context has the flag :

    // Use the text provided in FinalStepAsync or the default if it is the first time.
        var messageText = stepContext.Options?.ToString() ?? "welcome-message";
        if (messageText.Equals(FLAG_REPROMPT))
        {
            return await stepContext.NextAsync(null,cancellationToken);
        }

Later this you are in the second step