install-package Microsoft.CognitiveServices.Speech
install-package NAudio
install-package System.Speech

using Microsoft.CognitiveServices.Speech;
using Microsoft.CognitiveServices.Speech.Audio;

using NAudio.CoreAudioApi;

using System;
using System.Speech.Recognition;

namespace ConsoleApp1
{
    class Program
    {
        static SpeechConfig speechConfig = SpeechConfig.FromSubscription("<paste-your-subscription-key>", "<paste-your-region>");
        static string id = "";
        static AudioConfig audioConfig = AudioConfig.FromMicrophoneInput(id);
        static SpeechSynthesizer sy = new SpeechSynthesizer(speechConfig, audioConfig);
        static void Main(string[] args)
        {
            var enumerator = new MMDeviceEnumerator();
            var id = "";
            foreach (var endpoint in
                     enumerator.EnumerateAudioEndPoints(DataFlow.Capture, DeviceState.Active))
            {
                Console.WriteLine("{0} ({1})", endpoint.FriendlyName, endpoint.ID);
                id = endpoint.ID;
            }

            //创建中午识别器
            using (SpeechRecognitionEngine recognizer = new SpeechRecognitionEngine(new System.Globalization.CultureInfo("zh-CN")))
            {
                //----------------
                //初始化命令词
                Choices conmmonds = new Choices();
                //添加命令词
                conmmonds.Add(new string[] { "吃饭", "拿可乐", "拿玩具" });
                //初始化命令词管理
                GrammarBuilder gBuilder = new GrammarBuilder();
                //将命令词添加到管理中
                gBuilder.Append(conmmonds);
                //实例化命令词管理
                System.Speech.Recognition.Grammar grammar = new System.Speech.Recognition.Grammar(gBuilder);
                //-----------------
                //创建并加载听写语法(添加命令词汇识别的比较精准)
                recognizer.LoadGrammar(grammar);
                //为语音识别事件添加处理程序。
                recognizer.SpeechRecognized += new EventHandler<SpeechRecognizedEventArgs>(recognizer_SpeechRRecongized);
                //将输入配置到语音识别器。
                recognizer.SetInputToDefaultAudioDevice();
                //启动异步，连续语音识别。
                recognizer.RecognizeAsync(RecognizeMode.Multiple);

                //保持控制台窗口打开。
                while (true)
                {
                    Console.ReadLine();
                }

            }
        }

        //speechrecognized事件处理
        static void recognizer_SpeechRRecongized(object sender, SpeechRecognizedEventArgs e)
        {
            Console.WriteLine("识别结果：" + e.Result.Text);
        }
    }
}

[HttpPost]
        public object Send(IFormFile file)
        {
            var stream = file.OpenReadStream();

            var sr = new StreamReader($"{Environment.CurrentDirectory}\\words.txt");
            var txt = sr.ReadToEnd();
            var Words = txt.Split(Environment.NewLine);
            sr.Dispose();
            using (var recognizer = new SpeechRecognitionEngine(new System.Globalization.CultureInfo("zh-CN")))
            {
                //----------------
                //初始化命令词
                var conmmonds = new Choices();
                //添加命令词
                conmmonds.Add(Words);
                //初始化命令词管理
                var gBuilder = new GrammarBuilder();
                //将命令词添加到管理中
                gBuilder.Append(conmmonds);
                //实例化命令词管理
                var grammar = new System.Speech.Recognition.Grammar(gBuilder);
                //-----------------
                //创建并加载听写语法(添加命令词汇识别的比较精准)
                recognizer.LoadGrammar(grammar);
                recognizer.SetInputToWaveStream(stream);

                //为语音识别事件添加处理程序。
                recognizer.SpeechRecognized += new EventHandler<SpeechRecognizedEventArgs>(recognizer_SpeechRecognized);
                recognizer.RecognizeCompleted += new EventHandler<RecognizeCompletedEventArgs>(recognizer_RecognizeCompleted);
                //将输入配置到语音识别器。
                //recognizer.SetInputToDefaultAudioDevice();
                //启动异步，连续语音识别。
                //recognizer.RecognizeAsync(RecognizeMode.Single);
                recognizer.InitialSilenceTimeout = TimeSpan.FromSeconds(10);
                completed = false;
                var result = recognizer.Recognize(recognizer.InitialSilenceTimeout);
                //while (!completed)
                //{
                //    Thread.Sleep(300);
                //}
                return new { Success = true, Data = result?.Text };

            }
        }