C# 根据给定 小时 分钟 计算给定时间段的偏差时长

 private void button5_Click(object sender, EventArgs e)
        {
            string str = "8.00~12.30";
            int index = str.IndexOf('~');
            int length = str.Length - index - 1;
            string begin = str.Substring(0, index);
            string end = str.Substring(index + 1, length);

            string timea = "8:30";
            string timeb = "11:30";
            DateTime beginTime = Convert.ToDateTime(timea);
            DateTime endTime = Convert.ToDateTime(timeb);

            var aaa = GetTimeLength(beginTime, endTime);
            var bbb = GetTimeLenght2(beginTime, endTime);
            MessageBox.Show("GetTimeLength==" + aaa + "
" + bbb);
        }

        public string GetTimeLength(DateTime beginTime, DateTime endTime)
        {
            try
            {
                string timeLength = string.Empty;
                TimeSpan begin = new TimeSpan(beginTime.Ticks);
                TimeSpan end = new TimeSpan(endTime.Ticks);
                TimeSpan ts = begin.Subtract(end).Duration();

                timeLength = Convert.ToString(ts.Hours * 60 + ts.Minutes);

                return timeLength;
            }
            catch
            {
            }
            return string.Empty;
        }


        public string GetTimeLenght2(DateTime DateTime1, DateTime DateTime2)
        {
            string dateDiff = string.Empty;
            try
            {
                TimeSpan ts1 = new TimeSpan(DateTime1.Ticks);
                TimeSpan ts2 = new TimeSpan(DateTime2.Ticks);
                TimeSpan ts = ts1.Subtract(ts2).Duration();
                string hours = ts.Hours.ToString(), minutes = ts.Minutes.ToString(), seconds = ts.Seconds.ToString();
                if (ts.Hours < 10)
                {
                    hours = "0" + ts.Hours.ToString();
                }
                if (ts.Minutes < 10)
                {
                    minutes = "0" + ts.Minutes.ToString();
                }
                if (ts.Seconds < 10)
                {
                    seconds = "0" + ts.Seconds.ToString();
                }
                dateDiff = hours + ":" + minutes + ":" + seconds;
            }
            catch
            {
            }
            return dateDiff;
        }