计算一年中的第几周/c#得到阳历对应农历日期

一周从周日算起
DateTime mDatetime=new DateTime(year,1,1);//year为要求的那一年
int firstweekfirstday=Convert.ToInt32(mDTime.DayOfWeek);//一年中第一天是周几
days=(double)(6-firstweekfirstday);
DateTime secondweekfisrtday=mDTime.AddDays(days);第二周一
fisrtday=MDatetime.AddDays(week*7);//第N周第一天
lastday=MDatetime.AddDays(week*7+6);//第N周最后一天

一周从周一算起
DateTime mDatetime=new DateTime(year,1,1);//year为要求的那一年
int firstweekfirstday=Convert.ToInt32(mDTime.DayOfWeek);//一年中第一天是周几
days=(double)(7-firstweekfirstday);
DateTime secondweekfisrtday=mDTime.AddDays(days);第二周一
fisrtday=MDatetime.AddDays(week*7);//第N周第一天
lastday=MDatetime.AddDays(week*7+6);//第N周最后一天

javascript:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<SCRIPT LANGUAGE="JavaScript" type="text/javascript">
function showDateCount(year,weekNum){
var date=new Date(year,0,(7*weekNum));
var FD=new Date(date.getYear(),(date.getMonth()),(date.getDate()-date.getDay()+1))
var Monday=FD.getYear()+"-"+(FD.getMonth()+1)+"-"+FD.getDate()//一周的第一天

var LD=new Date(date.getYear(),(date.getMonth()),(date.getDate()-date.getDay()+7))
var Sunday=LD.getYear()+"-"+(LD.getMonth()+1)+"-"+LD.getDate() //一周的最后一天
alert(year+"年第"+weekNum+"周是"+Monday+"至"+Sunday)
}
</SCRIPT>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
</HEAD>

</BODY>
</HTML>

c#
//monthCalendar1是日历控件
System.Globalization.ChineseLunisolarCalendar c = new ChineseLunisolarCalendar();
        private void monthCalendar1_DateChanged(object sender, DateRangeEventArgs e)
        {
            DateTime MySelectDate = e.End;
            txt_nonglidate.Text = string.Format(CultureInfo.InstalledUICulture, "{0}-{1}-{2}", c.GetYear(MySelectDate), c.GetMonth(MySelectDate), c.GetDayOfMonth(MySelectDate));
        }