Exception in BOT Framework application in a FormBu

Question

I am getting below error in FormFlow. A quick help is really appreciable.

Exception: anonymous method closures that capture the environment are not serializable, consider removing environment capture or using a reflection serialization surrogate: FlightBot.FlightManager+<>c__DisplayClass2_0", "attachments": [ { "contentType": "text/plain", "content": " at Microsoft.Bot.Builder.Internals.Fibers.Serialization.ClosureCaptureErrorSurrogate.System.Runtime.Serialization.ISerializationSurrogate.GetObjectData(Object obj, SerializationInfo info, StreamingContext context)

After searching on StackOverflow and GitHub I got a piece of a code which says that "You need to register it in autofac container".

So I placed below code in WebAPIConfig.cs

    var builder = new ContainerBuilder();
    builder.RegisterModule(new ReflectionSurrogateModule());
    builder.Update(Conversation.Container);

But still I got an error, but this time error was different compared to previous and it is given below,

"Exception: Cannot serialize delegates over unmanaged function pointers, dynamic methods or methods outside the delegate creator's assembly.", "attachments": [ { "contentType": "text/plain", "content": " at System.MulticastDelegate.GetObjectData(SerializationInfo info, StreamingContext context)\r\n at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder)\r\n

I have copied the complete code of my application over here.

1. First part is MessagesController class from where I call FlightManager which is a LUIS dialog.
2. The second part of the code is FlightManager class from where I call FlightBooking class.

3. Third is actual flight booking class.

   [BotAuthentication]
   public class MessagesController : ApiController
   {
       internal static IDialog<object> MakeRootDialog()
       {
           return Chain.From(() => new FlightManager());
       }
   
       public async Task<HttpResponseMessage> Post([FromBody]Activity activity)
       {
           if (activity.Type == ActivityTypes.Message)
           {
               await Conversation.SendAsync(activity, MakeRootDialog);
           }
           else
           {
               HandleSystemMessage(activity);
           }
           var response = Request.CreateResponse(HttpStatusCode.OK);
           return response;
       }
   
       private Activity HandleSystemMessage(Activity message)
       {
           if (message.Type == ActivityTypes.DeleteUserData)
           {
               // Implement user deletion here
               // If we handle user deletion, return a real message
           }
           else if (message.Type == ActivityTypes.ConversationUpdate)
           {
               // Handle conversation state changes, like members being added and removed
               // Use Activity.MembersAdded and Activity.MembersRemoved and Activity.Action for info
               // Not available in all channels
           }
           else if (message.Type == ActivityTypes.ContactRelationUpdate)
           {
               // Handle add/remove from contact lists
               // Activity.From + Activity.Action represent what happened
           }
           else if (message.Type == ActivityTypes.Typing)
           {
               // Handle knowing tha the user is typing
           }
           else if (message.Type == ActivityTypes.Ping)
           {
           }
   
           return null;
       }
   }
   

---

namespace FlightBot
{
    [LuisModel("luis model key", "luis secret")] 
    [Serializable]
    public class FlightManager : LuisDialog<object>
    {
        public async Task FlightBookingTask(IDialogContext context, LuisResult result)
        {
            PromptDialog.Confirm(
                context: context,
                resume: ResumeAndHandleConfirmAsync,
                prompt: $"It seems you wish to book a flight. Do you wish to continue?",
                retry: "I didn't understand. Please try again.");
        }

        private async Task ResumeAndHandleConfirmAsync(IDialogContext context, IAwaitable<bool> argument)
        {
            FlightBooking cb = new FlightBooking();
            BuildFormDelegate<FlightBooking> MakeFlightBookingForm = () => FlightBooking.BuildForm(context);
            var flightBooking = new FormDialog<FlightBooking>(cb, MakeFlightBookingForm, FormOptions.PromptInStart, null);
            context.Call(flightBooking, FlightBookingComplete);
        }

        private async Task FlightBookingComplete(IDialogContext context, IAwaitable<FlightBooking> result)
        {
            context.Wait(MessageReceived);
        }
    }
}

---

namespace FlightBot
{
    [Serializable]
    public class FlightBooking
    {
        [Prompt("Enter source :")]
        public string Source { get; set; }

        [Prompt("Enter destination :")]
        public string Destination { get; set; }

        public static IForm<FlightBooking> BuildForm(IDialogContext context)
        {
            return new FormBuilder<FlightBooking>().Message("Tell me about flight details!")
           .Field(nameof(Source))
           .Field(nameof(Destination))
           .Build();

        }
    }
}

---

Answer 1

I have had the first exception and from what I have learned, you cannot send parameters when you call the form builder method in this line:

BuildFormDelegate<FlightBooking> MakeFlightBookingForm = () => FlightBooking.BuildForm(context);

So make sure you declare the method without any parameters:

public static IForm<FlightBooking> BuildForm()
{ //code   }

I hope this could help you, good luck with your bot!