C#_计算目前时间到指定的周X、指定的时间X 还有多少秒

比如：当前时间到下周二 05:00:00还剩下多少秒？

 /// <summary>
 /// 计算距离下一个 周XX XX时XX分XX秒，还剩下多少秒
 /// </summary>
 /// <param name="currDateTime">当时间</param>
 /// <param name="dayWeek">目标星期</param>
 /// <param name="str_HourMinuteSecond">目标时间,时分秒的字符串格式 "05:00:00"</param>
 /// <param name="totalSeconds">计算结果:还剩下的总秒数</param>
 void CalEndTimeSeconds(DateTime currDateTime, DayOfWeek dayWeek, string str_HourMinuteSecond, out int totalSeconds)
 {
     totalSeconds = ;
     TimeSpan tp = new TimeSpan();
     if (TimeSpan.TryParse(str_HourMinuteSecond, out tp))
     {
         int endPointSeconds = (int)tp.TotalSeconds;

         int currDayPassSeconds = (int)currDateTime.TimeOfDay.TotalSeconds;

         //当天还剩下的秒数
         totalSeconds = currDayPassSeconds <= endPointSeconds ? (endPointSeconds - currDayPassSeconds) : (perDaySeconds - currDayPassSeconds);

         if (currDateTime.DayOfWeek > dayWeek)
         {
             int days =  - (int)currDateTime.DayOfWeek;
             totalSeconds += days * perDaySeconds;
             totalSeconds += endPointSeconds;
         }
         else if (currDateTime.DayOfWeek == dayWeek)
         {
             totalSeconds += ;
         }
         else
         {
             int days = (int)(dayWeek - currDateTime.DayOfWeek) - ;
             totalSeconds += days * perDaySeconds;
             totalSeconds += endPointSeconds;
         }
     }
 }