计算两个日期之间的间隔天数、周末天数、以及为当年的哪一周

[color=#008080]//获得当前日期为一年中的第几周[/color]
public static int GetWeekOfYear(DateTime dt)
{
CultureInfo ci = CultureInfo.CurrentCulture;
System.Globalization.Calendar cal = ci.Calendar;
CalendarWeekRule cwr = ci.DateTimeFormat.CalendarWeekRule;
DayOfWeek dow = ci.DateTimeFormat.FirstDayOfWeek;
return cal.GetWeekOfYear(dt,cwr,dow);
}

[color=#008080]//获得连个日期间的周末天数[/color]
public static int WeekDays(string startDate,string endDate)
{
DateTime stDateTime = Convert.ToDateTime(startDate);
DateTime enDateTime = Convert.ToDateTime(endDate);

int stWeekOfYear = GetWeekOfYear(stDateTime);
int enWeekOfYear = GetWeekOfYear(enDateTime);

int stDayOfWeek = (int)stDateTime.DayOfWeek;
int enDayOfWeek = (int)enDateTime.DayOfWeek;

int weekendDays = (enWeekOfYear - stWeekOfYear) * 2;

if(stDayOfWeek == 0) weekendDays += 1;
if(enDayOfWeek == 6) weekendDays += 1;

return weekendDays;
}

[color=#008080]//获得两个日期间的时间间隔[/color]
public static int IntervalDays(string startDate,string endDate)
{
DateTime stDateTime = Convert.ToDateTime(startDate);
DateTime enDateTime = Convert.ToDateTime(endDate);

int stDayOfYear = stDateTime.DayOfYear;
int enDayOfYear = enDateTime.DayOfYear;

int intervalDays = enDayOfYear - stDayOfYear + 1;

return intervalDays;
}

之前有用到，查了很多资料后整理出来的，希望有用...