Junstyle's Blog

判断两个日期是否在同一周

/// <summary>
/// 判断两个日期是否在同一周
/// </summary>
/// <param name="dtmS">开始日期</param>
/// <param name="dtmE">结束日期</param>
/// <returns></returns>
private bool IsInSameWeek(DateTime dtmS, DateTime dtmE)
{
	TimeSpan ts=dtmE - dtmS;
	double dbl=ts.TotalDays;
	int intDow=Convert.ToInt32(dtmE.DayOfWeek);
	if(intDow==0)
		intDow=7;

	if(dbl>=7 || dbl>=intDow)
		return false;
	else
		return true;
}

某日期是本月的第几周

private int WeekOfMonth(DateTime dtSel, bool sundayStart)
{
     //如果要判断的日期为1号，则肯定是第一周了
     if (dtSel.Day == 1)
         return 1;
     else
     {
         //得到本月第一天
         DateTime dtStart = new DateTime(dtSel.Year, dtSel.Month, 1);

        //得到本月第一天是周几
        int dayofweek = (int)dtStart.DayOfWeek;

        //如果不是以周日开始，需要重新计算一下dayofweek，详细风DayOfWeek枚举的定义
        if (!sundayStart)
        {
            dayofweek = dayofweek - 1;
            if (dayofweek < 0)
                dayofweek = 7;
        }

        //得到本月的第一周一共有几天
        int startWeekDays = 7 - dayofweek;

       //如果要判断的日期在第一周范围内，返回1
        if (dtSel.Day <= startWeekDays)
            return 1;
        else
        {
            int aday = dtSel.Day + 7 - startWeekDays;
            return aday / 7 + (aday % 7 > 0 ? 1 : 0);
        }
    }
}