找不到类型或命名空间名称luisresult

我有一个C#chatbot,我想将LUIS API连接到它,但我一直收到以下错误: 找不到类型或命名空间名称luisresult 我如何解决这个错误?

 private async Task DispatchToTopIntentAsync(ITurnContext<IMessageActivity> turnContext, string intent, RecognizerResult recognizerResult, CancellationToken cancellationToken)
    {
        switch (intent)
        {
            case "Approval":
            
                await ProcessCovid19LuisAsync(turnContext, recognizerResult.Properties["luisResult"] as LuisResult, cancellationToken);
                break;
            // case "l_Weather":
            //     await ProcessWeatherAsync(turnContext, recognizerResult.Properties["luisResult"] as LuisResult, cancellationToken);
            //     break;
            
            default:
                _logger.LogInformation($"Covid19Bot unrecognized you.");
                await turnContext.SendActivityAsync(MessageFactory.Text($"Covid19Bot unrecognized you, kindly type a question as what is the symptoms of covid19."), cancellationToken);
                break;
        }