QNAMaker GetAnswer API with Custom question answering

Question

I have a chatbot setup with QNAMaker and a custom c# bot to query knowledge base. Bot builder 4.2 package is being used. Below is the typical QNAMaker KB details and this works.

Below is the details in c# bot chatbot.bot file. Details have been added from the above

    {
      "type": "qna",
      "KbId": "13xxx-xxx-xxx-xx",
      "endpointKey": "89xxx-xxxx-xxx",
      "hostname": "https://xxx.azurewebsites.net/qnamaker",
      "id": "117",
      "name": "QnAMaker-en",
      "subscriptionKey": ""
    },

Get answer is called in the bot as shown below. More details here

var response = await _service.GetAnswersAsync(stepContext.Context).ConfigureAwait(false);

The above works, with response always has answer from QNAMaker KB.

Recently i plan to use Custom Question Answering. I have created a Knowledge base with Text analytics. After i published this Knowledge base i see the different key to access. Below is the details

I no longer see the Endpoint key instead i get a Ocp-Apim-Subscription-Key. How do make use of this new KB in existing bot. What change is needed in chatbot.bot file? When i try to use Ocp-Apim-Subscription-Key as Endpoint key in chatbot.bot file the GetAnswer response is always null.

{
      "type": "qna",
      "KbId": "78xxx-xxx-xxx",
      "endpointKey": "8exxxxx",
      "hostname": "https://xxxxxx.cognitiveservices.azure.com/qnamaker/v5.0-preview.2",
      "id": "117",
      "name": "QnAMaker-en",
      "subscriptionKey": "8exxxxx"
    },

Answer 1

Incase anyone needs it, i went with Custom Question Answering SDK (Azure.AI.Language.QuestionAnswering).

            Uri endpoint = new Uri("https://{YOUR-ENDPOINT}.api.cognitive.microsoft.com/");
            AzureKeyCredential credential = new AzureKeyCredential("{YOUR-LANGUAGE-RESOURCE-KEY}");
            string projectName = "{YOUR-PROJECT-NAME}";
            string deploymentName = "production";

            string question = "How long should my Surface battery last?";

            QuestionAnsweringClient client = new QuestionAnsweringClient(endpoint, credential);
            QuestionAnsweringProject project = new QuestionAnsweringProject(projectName, deploymentName);

            Response<AnswersResult> response = client.GetAnswers(question, project);

            foreach (KnowledgeBaseAnswer answer in response.Value.Answers)
            {
                Console.WriteLine($"Q:{question}");
                Console.WriteLine($"A:{answer.Answer}");
            }