endTime.Subtract(startTime).TotalMilliseconds;

       private string DateDiff(DateTime DateTime1, DateTime DateTime2)
       {
           string dateDiff = null;
           try
           {
               TimeSpan ts1 = new TimeSpan(DateTime1.Ticks);
               TimeSpan ts2 = new TimeSpan(DateTime2.Ticks);
               TimeSpan ts = ts1.Subtract(ts2).Duration();
               dateDiff = ts.TotalMilliseconds.ToString();
           }
           catch
           {

           }
           return dateDiff;
       }