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 accordin

Answer 1

I'm not sure, if it's the right and efficient way to do it, but you can experiment with the State property of the context.ActiveDialog within your Task<DialogTurnResult> function.

context.ActiveDialog.State["stepIndex"] = (int)context.ActiveDialog.State["stepIndex"] -2;

Answer 2

Waterfall dialogs weren't designed with the idea of 'going backwards' to traverse them, though I can see the possible need to. The only solution I've found is to break your waterfall into smaller "mini" waterfalls, and nest them into one larger waterfall.

        // define and add waterfall dialogs (main)
        WaterfallStep[] welcomeDialogSteps = new WaterfallStep[]
        {
            MainDialogSteps.PresentMenuAsync,
            MainDialogSteps.ProcessInputAsync,
            MainDialogSteps.RepeatMenuAsync,
        };

Then in MainDialogSteps.ProcessInputAsync:

        public static async Task<DialogTurnResult> ProcessInputAsync(
            WaterfallStepContext stepContext,
            CancellationToken cancellationToken)
        {
            var choice = (FoundChoice)stepContext.Result;
            var dialogId = Lists.WelcomeOptions[choice.Index].DialogName;

            return await stepContext.BeginDialogAsync(dialogId, null, cancellationToken);
        }

This allows the users to start new dialogs still within the main dialog stack. One of my options I offered was a prompt of a list of phone numbers:

        WaterfallStep[] phoneChoiceDialogSteps = new WaterfallStep[]
        {
            PhoneChoicePromptSteps.PromptForPhoneAsync,
            PhoneChoicePromptSteps.ConfirmPhoneAsync,
            PhoneChoicePromptSteps.ProcessInputAsync,
        };

        Add(new WaterfallDialog(Dialogs.PhonePrompt, phoneChoiceDialogSteps));

And finally, in the PhoneChoicePromptSteps.ProcessInputAsync, I allowed for the selection of 'no' from the confirm to ReplaceDialogAsync and effectivly reset this smaller waterfall, without effecting the rest of the overall waterfall:

 public static async Task<DialogTurnResult> ProcessInputAsync(
            WaterfallStepContext stepContext,
            CancellationToken cancellationToken)
        {
            if ((bool)stepContext.Result)
            {
                await stepContext.Context.SendActivityAsync(
                    $"Calling {stepContext.Values[Outputs.PhoneNumber]}",
                    cancellationToken: cancellationToken);
                return await stepContext.EndDialogAsync(null, cancellationToken);
            }
            else
            {
                return await stepContext.ReplaceDialogAsync(Dialogs.PhonePrompt, null, cancellationToken);
            } 
        }

Answer 3

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