Autofac或Delegates的工作方式是在ASP.Net Web API Bot Framework中加载错误的依赖项

Question

Since the Microsoft Bot Framework is using Autofac as a dependency, I figured I'd use it in the rest of my project (using the Bot Framework project scaffold ). I'm trying to load the correct Bot Framework IDialog using DI. My Global.asax.cs looks like this:

protected void Application_Start()
{
    GlobalConfiguration.Configure(WebApiConfig.Register);

    var builder = new ContainerBuilder();            

    // Get your HttpConfiguration.
    var config = GlobalConfiguration.Configuration;

    // Register your Web API controllers.
    builder.RegisterApiControllers(Assembly.GetExecutingAssembly());

    // OPTIONAL: Register the Autofac filter provider.
    builder.RegisterWebApiFilterProvider(config);

    builder.RegisterType<EchoDialogState>().Named<IDialog<object>>(ActivityTypes.Message);
    builder.RegisterType<WelcomeDialog1>().Named<IDialog<object>>(ActivityTypes.ConversationUpdate);
    builder.RegisterType<UnknownDialog>().Named<IDialog<object>>(string.Empty).PreserveExistingDefaults();

    // Set the dependency resolver to be Autofac.
    var container = builder.Build();
    config.DependencyResolver = new AutofacWebApiDependencyResolver(container);            
}

The ActivityTypes are string constants that equate to message , conversationUpdate , etc. For my controllers, I have a base that looks like this to resolve the Autofac DI Container:

public class BaseApiController : ApiController
{
    public IContainer Container { get; private set; } = ((IContainer)((AutofacWebApiDependencyResolver)GlobalConfiguration.Configuration.DependencyResolver).Container);
}

In my MessagesController that catches all bot interactions, my code looks like this:

[BotAuthentication]
public class MessagesController : BaseApiController
{

    public virtual async Task<HttpResponseMessage> Post([FromBody] Activity activity)
    {
        using (var scope = Container.BeginLifetimeScope())
        {
            var dialog = scope.ResolveNamed<IDialog<object>>(activity.GetActivityType());

            await Conversation.SendAsync(activity, () => dialog);
        }

        return new HttpResponseMessage(System.Net.HttpStatusCode.Accepted);
    }
}

The activity.GetActivityType() simply returns back a string with equates with the ActivityTypes referred to above. When I breakpoint on scope.ResolveNamed , it looks like the correct IDialog has been returned to dialog . However, when the Conversation.SendAsync runs, the wrong IDialog is running. For example, I see EchoDialogState being injected into dialog , but then the code inside WelcomeDialog1 is always being called instead.

Am I doing this wrong? What would cause the incorrect IDialog being run inside the delegate function?

If it helps, this is an example of the IDialog that's running:

[Serializable]
public class WelcomeDialog1 : IDialog<object>
{
    public async Task StartAsync(IDialogContext context)
    {
        context.Wait(MessageReceivedAsync);
    }
    public async Task MessageReceivedAsync(IDialogContext context, IAwaitable<IMessageActivity> argument)
    {
        var message = await argument;
        var name = message.From.Name;

        await context.PostAsync($"Hi {name}. Welcome to SMEBot! First time here stuff.");
        context.Wait(MessageReceivedAsync);
    }
}

Answer 1

Instead of doing a context.Wait in the MessageReceivedAsync method of your WelcomeDialog1, try doing a context.Done.

In the way you are doing it now, the WelcomeDialog1 is still listening to your messages. Usually the welcome message is done using the ConnectorClient in the MessageController as it is a simple message. You don't need all the dialog infrastructure.