Compare double value of stopwatch

[ken4ward]

 private void comboBoxItemsforAlarm_SelectedIndexChanged(object sender, EventArgs e)
        {
            stopWatch.Restart();
double doubleStopWatch = Convert.ToDouble(stopWatch.Elapsed.Hours + "." + stopWatch.Elapsed.Minutes);
                double timeAlarm = Convert.ToDouble(maskedTime.Text.ToString());
                if (doubleStopWatch == timeAlarm)
                {
                    mediaSoundPlayer.Stream = Properties.Resources.Song_of_Song; ;
                mediaSoundPlayer.PlayLooping();
                 }
        }

please i try to compare a stopwatch converted to a double value and a value from a textbox converted to a double value it seems not to do the comparison because it does not play the file when both are equal. what should i do?