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Waterfall Model In Microsoft Bot Framework

What Is A Waterfall Model?

Implementation

1. Create a new class "RootDialog" that implements "ComponentDialog".

public class RootDialog : ComponentDialog{ 
} 




2. In "Startup.cs", add the following code.

services.AddSingleton<RootDialog>(); 
services.AddTransient<IBot, Karan_EchoBot.Bots.EchoBot<RootDialog>>(); 




3. Change the definition of “EchoBot”.

public class EchoBot < T >: ActivityHandler where T: Microsoft.Bot.Builder.Dialogs.Dialog { 
    private IConfiguration _configuration; 
    private UserState _userState; 
    private ConversationState _conversationState; 
  
    private Microsoft.Bot.Builder.Dialogs.Dialog _dialog; 
  
    private IStatePropertyAccessor < UserData > _userData; 
    private IStatePropertyAccessor < ConversationData > _conversationData; 
  
    public EchoBot(IConfiguration configuration, UserState userState, ConversationState conversationState, T dialog) { 
        _configuration = configuration; 
        _userState = userState; 
        _conversationState = conversationState; 
  
        this._dialog = dialog; 
  
        _userData = userState.CreateProperty < UserData > ("UserData"); 
        _conversationData = conversationState.CreateProperty < ConversationData > ("ConversationData"); 
    } 
} 




4. In the "OnMessageActivityAsync" method, call the "RootDialog" class.

protected override async Task OnMessageActivityAsync(ITurnContext < IMessageActivity > turnContext, CancellationToken cancellationToken) { 
    await _dialog.RunAsync(turnContext, _conversationState.CreateProperty <DialogState> ("DialogState"), cancellationToken); 
} 




5. Implement a waterfall model in "RootDialog.cs".

using Microsoft.Bot.Builder; 
using Microsoft.Bot.Builder.Dialogs; 
using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Threading; 
using System.Threading.Tasks; 
  
namespace Karan_EchoBot.Dialog { 
    public class RootDialog: ComponentDialog { 
        public RootDialog(): base(nameof(RootDialog)) { 
            var steps = new WaterfallStep[] { 
                FirstStep, 
                SecondStep 
            }; 
  
            AddDialog(new WaterfallDialog("WaterFallId", steps)); 
        } 
  
        private async Task < DialogTurnResult > SecondStep(WaterfallStepContext stepContext, CancellationToken cancellationToken) { 
            await stepContext.Context.SendActivityAsync(MessageFactory.Text("This is the second message"), cancellationToken); 
            return await stepContext.EndDialogAsync(null); 
        } 
  
        private async Task < DialogTurnResult > FirstStep(WaterfallStepContext stepContext, CancellationToken cancellationToken) { 
            await stepContext.Context.SendActivityAsync(MessageFactory.Text("This is the first message"), cancellationToken); 
            return Microsoft.Bot.Builder.Dialogs.Dialog.EndOfTurn; 
        } 
    } 
} 

Output