/// <summary>

/// 获取指定日期，在为一年中为第几周

/// </summary>

/// <param name="dt">指定时间</param>

/// <reutrn>返回第几周</reutrn>

private static int GetWeekOfYear(DateTime dt)

{

   GregorianCalendar gc = new GregorianCalendar();

   int weekOfYear = gc.GetWeekOfYear(dt,CalendarWeekRule.FirstDay, DayOfWeek.Monday);

   return weekOfYear;

}

 

/// <summary>

/// 求某年有多少周

/// 返回 int

/// </summary>

/// <param name="strYear"></param>

/// <returns>int</returns>

public static int GetYearWeekCount(int strYear)

{

    string returnStr = "";

    System.DateTime fDt = DateTime.Parse(strYear.ToString() + "-01-01");

    int k = Convert.ToInt32(fDt.DayOfWeek);//得到该年的第一天是周几

    if (k == 1)

    {

        int countDay = fDt.AddYears(1).AddDays(-1).DayOfYear;

        int countWeek = countDay / 7 + 1;

        return countWeek;

    }

    else

    {

        int countDay = fDt.AddYears(1).AddDays(-1).DayOfYear;

        int countWeek = countDay / 7 + 2;

        return countWeek;

    }

}

 

/// <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);

}

 

/// <summary>

/// 求某年有多少周

/// 返回 int

/// </summary>

/// <param name="strYear"></param>

/// <returns>int</returns>

public static int GetYearWeekCount(int strYear)

{

    string returnStr = "";

    System.DateTime fDt = DateTime.Parse(strYear.ToString() + "-01-01");

    int k = Convert.ToInt32(fDt.DayOfWeek);//得到该年的第一天是周几

    if (k == 1)

    {

        int countDay = fDt.AddYears(1).AddDays(-1).DayOfYear;

        int countWeek = countDay / 7 + 1;

        return countWeek;

    }

    else

    {

        int countDay = fDt.AddYears(1).AddDays(-1).DayOfYear;

        int countWeek = countDay / 7 + 2;

        return countWeek;

    }

}