How to Convert wav file to text file and stop Page execution in asp.net

protected void Button1_Click1(object sender, EventArgs e)
        {
            string text1 = ReadAudio();
            System.IO.File.WriteAllText(Server.MapPath("~/Uploads/Text/" + filenamewithoutextension + ".txt"), text1);
}
public string ReadAudio()
       {



           SpeechRecognitionEngine sre = new SpeechRecognitionEngine();
           Grammar gr = new DictationGrammar();
           sre.LoadGrammar(gr);

           sre.SetInputToWaveFile(bestpath);
           sre.BabbleTimeout = new TimeSpan(Int32.MaxValue);
           sre.InitialSilenceTimeout = new TimeSpan(Int32.MaxValue);
           sre.EndSilenceTimeout = new TimeSpan(100000000);
           sre.EndSilenceTimeoutAmbiguous = new TimeSpan(100000000);

           StringBuilder sb = new StringBuilder();
           while (true)
           {
               try
               {
                   var recText = sre.Recognize();
                   if (recText == null)
                   {
                       break;
                   }

                   sb.Append(recText.Text);
               }
               catch (Exception ex)
               {
                   //handle exception
                   //...

                   break;
               }
           }
           return sb.ToString();


       }

Hi Team,

i have send image of my asp page in that i am uploading wav file and converting to text and displaying to text area but the process is not complating please help me out from this problem.