Microsoft Bot Framework V4: System.NullReferenceException: 'Unable to locate SkillConversationIdFactoryBase in HostContext'

问题

I am working on creating a workflow which allows composer created dialogs to be integrated into a bot skill project.

To accomplish this I am trying to follow the instructions in this post: https://microsoft.github.io/botframework-solutions/skills/handbook/experimental-add-composer/

My composer created dialogs including calling a skill. When I initiate that intent through the Bot Emulator I get this error: System.NullReferenceException: 'Unable to locate SkillConversationIdFactoryBase in HostContext'

The setup to get to this error is time consuming so I have created a git repo which can be started fairly easily to demonstrate the issue.

The project can be found here: https://github.com/silverbulletgt/Integrate-Composer-Dialog-Using-Skill

To recreate the issue:

Prerequisites

Install Bot Emulator: https://github.com/Microsoft/BotFramework-Emulator/blob/master/README.md

Open the solution file in visual studio Integrate-Composer-Dialog-Using-Skill.sln

Put a breakpoint on line 72 of DefaultAdapter.cs - this is where the error can be seen

Start debugging the project

Open Bot Emulator

Connect to the bot: http://localhost:3978/api/messages

Type "Greeting"

Bot should respond with "Hello, I have recognized that you said greeting" - This means that the composer dialog integration is working as expected.

Type "Skill"

The breakpoint on line 72 of DefaultAdapter.cs should trigger giving details of the error.

Error & stack trace can be found here: https://github.com/silverbulletgt/Integrate-Composer-Dialog-Using-Skill/blob/master/Readme/error%20stack%20trace.txt

Edit: I was able to compile the Bot Builder code Bot Builder GitHub & connect it to my project so that I could debug. I found the error to be happening on line 157 of Microsoft.Bot.Builder.Dialogs.Adaptive.BeginSkill.cs code BeginSkill.cs.

This line is trying to get the SkillConversationFactoryBase out of the dialogContext.Context.TurnState. I'm investigating how I might add this so that it is populated when this code executes.

回答1:

Fix: System.NullReferenceException: 'Unable to locate SkillConversationIdFactoryBase in HostContext' in Microsoft.Bot.Builder.Dialogs.Adaptive.Actions.BeginSkill

This error was being caused by missing dependency injection requirements. Added the below lines to Startup.cs

services.AddSingleton<SkillConversationIdFactoryBase, SkillConversationIdFactory>();
services.AddSingleton<HttpClient>(new HttpClient());
services.AddSingleton<BotFrameworkClient, BotFrameworkHttpClient>();

Added to DefaultAdapter.cs

New Field

private readonly SkillConversationIdFactoryBase _skillConversationIdFactoryBase;

New constructor parameters

SkillConversationIdFactoryBase skillConversationIdFactoryBase,
BotFrameworkClient botFrameworkClient

To the body of the constructor

_skillConversationIdFactoryBase = skillConversationIdFactoryBase;

Use(new RegisterClassMiddleware<SkillConversationIdFactoryBase>(_skillConversationIdFactoryBase));
Use(new RegisterClassMiddleware<BotFrameworkClient>(botFrameworkClient));

This fixed the initial exception however there was then a new exception when the skill was called.

Exception wasOperation returned an invalid status code 'NotFound' at Microsoft.Bot.Connector.Conversations.d__10.MoveNext()

Fixing Operation returned an invalid status code 'NotFound' This exception was occurring because there was no endpiont api/skills. I suppose that the Bot Composer adds this endpoint automatically somehow.

I added SkillController.cs based on the example here: Bot Builder Tests JSON SkillController

Then added dependency injection to support the controller. Added to Startup.cs

services.AddSingleton<ChannelServiceHandler, SkillHandler>();
            services.AddSingleton<BotAdapter>(sp => (BotFrameworkHttpAdapter)sp.GetService<IBotFrameworkHttpAdapter>());

I tested a basic intent which does not use a skill to determine if there would be any conflict with the dependency injection impacting those. The basic intent worked as expected though.

I updated the master branch with the changes Project Repo

来源：https://stackoverflow.com/questions/65332422/microsoft-bot-framework-v4-system-nullreferenceexception-unable-to-locate-ski

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botframework