/// <summary>
        /// 試聽
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnListen_Click(object sender, EventArgs e)
        {
            string text = textBox1.Text;
            rate = this.cbxRate.SelectedIndex;

            if (text.Trim().Length == 0)
            {
                MessageBox.Show("不能閱讀空內(nèi)容!", "錯誤提示");
                return;
            }

            if (btnListen.Text == "語音試聽")
            {
                speech = new SpeechSynthesizer();
                new Thread(Speak).Start();
                btnListen.Text = "停止試聽";
            }
            else if (btnListen.Text == "停止試聽")
            {
                speech.SpeakAsyncCancelAll();//停止閱讀
                btnListen.Text = "語音試聽";
            }
        }

        private void Speak()
        {
            PromptBuilder builder = GetBuiltPrompt(this.textBox1.Text.ToString().Trim());
            speech.Rate = rate;
            speech.SelectVoice("Microsoft Huihui Desktop");//設(shè)置播音員（中文）
            speech.Volume = value;
            speech.SpeakAsync(builder);//語音閱讀方法
            speech.SpeakCompleted += speech_SpeakCompleted;//綁定事件
        }
        
        private PromptBuilder GetBuiltPrompt(string keywords)
        {
            //from http://msdn.microsoft.com/msdnmag/issues/06/01/speechinWindowsVista/ 
            //This prompt is quite complicated
            //So I'm going to build it first, and then render it.
            PromptBuilder myPrompt = new PromptBuilder();

            //Start the main speaking style
            PromptStyle mainStyle = new PromptStyle();
            mainStyle.Rate = PromptRate.NotSet;
            mainStyle.Volume = PromptVolume.Medium;
            // mainStyle.Emphasis=PromptEmphasis.Reduced;
            myPrompt.StartStyle(mainStyle);
            convert(myPrompt, keywords);
            myPrompt.EndStyle();
            return myPrompt;
        }

 		/// <summary>
        /// 轉(zhuǎn)義關(guān)鍵字
        /// </summary>
        private void convert(PromptBuilder myPrompt, string keywords)
        {
            //判斷是否存在要轉(zhuǎn)換的關(guān)鍵字
            Dictionary<int, string> convertCharacter = new Dictionary<int, string>();
            var kv_Index = keywords.IndexOf("kV");
            var sf6_Index = keywords.IndexOf("SF6");
            var point_index = keywords.IndexOf(".");
            if (kv_Index > -1)
            {
                convertCharacter.Add(kv_Index, "kv");
            }
            if (sf6_Index > -1)
            {
                convertCharacter.Add(sf6_Index, "sf6");
            }
            if (point_index > -1)
            {
                convertCharacter.Add(point_index, ".");
            }
            convertArray(convertCharacter, myPrompt, keywords);
        }
        
		/// <summary>
        /// 轉(zhuǎn)義關(guān)鍵字
        /// </summary>
        private void convertArray(Dictionary<int, string> convertCharacter, PromptBuilder myPrompt, string deviceName)
        { 
            string r = @"[0-9]+";
            Regex reg = new Regex(r, RegexOptions.IgnoreCase | RegexOptions.Singleline);//2秒后超時
            MatchCollection mc = reg.Matches(deviceName);//設(shè)定要查找的字符串 

            //按關(guān)鍵字升序排列
            convertCharacter = convertCharacter.OrderBy(t => t.Key).ToDictionary(p => p.Key, o => o.Value);
            int hasLen = 0;//記錄已經(jīng)截取的長度
            int splitNum = convertCharacter.Count;//要拆分的段數(shù)

            //針對有需要轉(zhuǎn)換的地方做特殊處理
            if (splitNum > 0)
            {
                for (var i = 0; i < splitNum; i++)
                {
                    var startIndex = convertCharacter.ElementAt(i).Key;//關(guān)鍵字開始的索引
                    var keyValue = convertCharacter.ElementAt(i).Value.ToLower();//關(guān)鍵字
                    var keyLen = keyValue.Length;//關(guān)鍵字對應(yīng)的長度 

                    //先把關(guān)鍵字前面的追加到標題
                    myPrompt.AppendText(deviceName.Substring(hasLen, startIndex - hasLen)); 
                    hasLen = startIndex + keyLen;//留做截取不是關(guān)鍵字的長度 
                    //判斷關(guān)鍵字的類型，確定轉(zhuǎn)換方式
                    if (keyValue == "kv")
                    {
                        myPrompt.AppendSsmlMarkup("<say-as interpret-as = \"kV\">千伏</say-as>");
                    }
                    else if (keyValue == "sf6")
                    {
                        myPrompt.AppendTextWithAlias("SF6", "六氟化硫");
                    }
                    else if (keyValue == "-")
                    {
                        myPrompt.AppendTextWithHint("-", SayAs.NumberCardinal);
                    }
                    else if (keyValue == ".")
                    {
                        myPrompt.AppendTextWithAlias(".", "點");
                    }  
                    //如果循環(huán)到最后一個關(guān)鍵字，再把最后一個關(guān)鍵字后邊的數(shù)追加上
                    if (i == splitNum - 1)
                    {
                        myPrompt.AppendText(deviceName.Substring(hasLen));
                    }
                } 
            }
            else
            {
                myPrompt.AppendText(deviceName);
            }
        }

  		/// <summary>
        /// 語音閱讀完成觸發(fā)此事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void speech_SpeakCompleted(object sender, SpeakCompletedEventArgs e)
        {
            //改變按鈕文本值
            ChangeBtnText changeBtnText = ChangeText;
            this.btnListen.BeginInvoke(changeBtnText);
        }
        
        /// <summary>
        /// 委托方法，改變按鈕值
        /// </summary>
        public void ChangeText()
        {
            btnListen.Text = "語音試聽";
        }