使用 System.Speech 可以很容易实现TTS。

原代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Speech.Synthesis;
using System.Text;
using System.Windows.Forms;

namespace ttsTest
{
    public partial class Form1 : Form
    {
        private SpeechSynthesizer synthes = null;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            synthes = new SpeechSynthesizer();
            trackBarVolume.Value = synthes.Volume;
            trackBarRate.Value = synthes.Rate;

            lblVolume.Text = "音量：" + trackBarVolume.Value;
            lblRate.Text = "语速：" + trackBarRate.Value;

            cmbVoice.BeginUpdate();
            cmbVoice.Items.Clear();
            foreach (var r in synthes.GetInstalledVoices())
            {
                if (r.Enabled)
                {
                    cmbVoice.Items.Add(r.VoiceInfo.Name);
                }
            }
            cmbVoice.EndUpdate();

            cmbVoice.SelectedItem = synthes.Voice.Name;
        }

        private void btnPlay_Click(object sender, EventArgs e)
        {
            string str = txtContent.Text.Trim();
            if (string.IsNullOrEmpty(str))
            {
                return;
            }

            synthes.SpeakAsyncCancelAll();
            synthes.SelectVoice(cmbVoice.SelectedItem.ToString());
            // synthes.SelectVoiceByHints(VoiceGender.Male, VoiceAge.Senior, 2, System.Globalization.CultureInfo.CurrentCulture);

            synthes.Volume = trackBarVolume.Value;
            synthes.Rate = trackBarRate.Value;//-10-10,值越小，语速越慢

            // synthes.Speak(txtContent.Text);//同步
            synthes.SpeakAsync(str);//异步
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            synthes.SpeakAsyncCancelAll();
        }

        private void trackBarVolume_Scroll(object sender, EventArgs e)
        {
            lblVolume.Text = "音量：" + trackBarVolume.Value;
        }

        private void trackBarRate_Scroll(object sender, EventArgs e)
        {
            lblRate.Text = "语速：" + trackBarRate.Value;
        }
    }
}