怎么知道一年有多少周？？？以及每个周的时间是多少号到多少号？ 例如 第一周 2007-X-X 到 2007-X-X 第二周 2007-X-X 到2007-X-X

    //返回第几周的日期
    //参数说明：
    //year：年份,month：月份;index：第几周
    private DateTime GetStartEndWeekOfMonth(int year, int month, int index)
    {
        DateTime startMonth = new DateTime(year, month, 1);
        DateTime endMonth = startMonth.AddMonths(1).AddDays(-1);
        int dayOfWeek = 7;
        if (Convert.ToInt32(startMonth.DayOfWeek.ToString("d")) > 0)
            dayOfWeek = Convert.ToInt32(startMonth.DayOfWeek.ToString("d"));
        DateTime startWeek = startMonth.AddDays(1 - dayOfWeek);
        DateTime startDayOfWeeks = startWeek.AddDays((index - 1) * 7);
        if ((startDayOfWeeks - startMonth.AddMonths(1)).Days > 0)
        {
             return DateTime.MinValue;
        }
        return startDayOfWeeks;//这是周一的日期，周末的加７就行了
    }

[[italic] 本帖最后由 sean88 于 2007-12-5 16:36 编辑 [/italic]]

/**/
    /// <summary>
    /// 得到一年中的某周的起始日和截止日
    /// 年 nYear
    /// 周数 nNumWeek
    /// 周始 out dtWeekStart
    /// 周终 out dtWeekeEnd
    /// </summary>
    /// <param name="nYear"></param>
    /// <param name="nNumWeek"></param>
    /// <param name="dtWeekStart"></param>
    /// <param name="dtWeekeEnd"></param>
    public static void GetWeek(int nYear, int nNumWeek, out   DateTime dtWeekStart, out   DateTime dtWeekeEnd)
    {
        DateTime dt = new DateTime(nYear, 1, 1);
        dt = dt + new TimeSpan((nNumWeek - 1) * 7, 0, 0, 0);
        dtWeekStart = dt.AddDays(-(int)dt.DayOfWeek + (int)DayOfWeek.Monday);
        dtWeekeEnd = dt.AddDays((int)DayOfWeek.Saturday - (int)dt.DayOfWeek + 1);
    }