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 = 0;
    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 = 7 - (int)currDateTime.DayOfWeek;
            totalSeconds += days * perDaySeconds;
            totalSeconds += endPointSeconds;
        }
        else if (currDateTime.DayOfWeek == dayWeek)
        {
            totalSeconds += 0;
        }
        else
        {
            int days = (int)(dayWeek - currDateTime.DayOfWeek) - 1;
            totalSeconds += days * perDaySeconds;
            totalSeconds += endPointSeconds;
        }
    }
}