使用 RecognizeAsync 启动识别器时出现 NullReferenceException

Question

嗨，我目前正在开发一个程序，该程序应该可以识别我的声音，然后写下它听到的内容，但是当我运行代码并单击按钮启动 recEngine 时，它说"An unhandled exception of type 'System.NullReferenceException' occurred in System.Speech.dll"，并且在提示中说有可能之前的var为null。但是我之前设置过变量还是我做错了什么。

这是代码

using System;
using System.Windows.Forms;
using System.Speech.Recognition;

namespace Voice_Recognition
{
    public partial class Form1 : Form
    {
        SpeechRecognitionEngine recEngine =  new SpeechRecognitionEngine();

        public Form1()
        {
            InitializeComponent();
        }

        private void BtnEnable_Click(object sender, EventArgs e)
        {

这是出现错误的行。

            recEngine.RecognizeAsync(RecognizeMode.Multiple);
            // BtnEnable.Enabled = false;
            BtnDisable.Enabled = true;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Choices commands = new Choices();
            commands.Add(new string[] { "say hello", "print my name" });
            GrammarBuilder Gbuilder = new GrammarBuilder();
            Gbuilder.Append(commands);
            Grammar grammar = new Grammar(Gbuilder);
            recEngine.LoadGrammarAsync(grammar);
            recEngine.SetInputToDefaultAudioDevice();
            recEngine.SpeechRecognized += recEngine_SpeechRecognized;
        }

        private void recEngine_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
        {
            switch (e.Result.Text)
            {
                case "say hello":
                    Log.Text += "\nHello";
                    break;
                case "print my name":
                    Log.Text += "\nMyname";
                    break;

            }
        }

        private void BtnDisable_Click(object sender, EventArgs e)
        {
            BtnEnable.Enabled = true;
            BtnDisable.Enabled = false;
            recEngine.RecognizeAsyncStop();
        }
    }
 }

在提示菜单中它说：

-调用方法前检查对象是否为空

-使用"new"关键字创建对象实例

提前致谢

Answer 1

一些看起来很奇怪的事情：

使用recEngine.SpeechRecognized += new EventHandler<SpeechRecognizedEventArgs>(recEngine_SpeechRecognized);代替recEngine.SpeechRecognized += recEngine_SpeechRecognized;
可能是你开始识别的时候语法还没有加载完成；使用 LoadGrammar 而不是 LoadGrammarAsync（或为 LoadGrammarCompleted 添加处理程序）。
我一直发现明确指定识别器（和语法）的文化信息很方便，因为这可以防止对使用的语言产生误解。

使用 RecognizeAsync 启动识别器时出现 NullReferenceException

NullReferenceException when starting recognizer with RecognizeAsync

speech-recognition

sapi