C#求今天是一年中的第几周怎么算？

C#求今天是一年中的第几周怎么算？

 private   int   WeekOfYear(string   date) 
{ 
DateTime   curDay   =   Convert.ToDateTime(date); 

int   firstdayofweek   =   Convert.ToInt32(Convert.ToDateTime(curDay.Year.ToString()   +   "- "   +   "1-1 ").DayOfWeek); 

int   days   =   curDay.DayOfYear; 
int   daysOutOneWeek   =   days   -   (7   -   firstdayofweek); 

if   (daysOutOneWeek   <=   0) 
{ 
return   1; 
} 
else 
{ 
int   weeks   =   daysOutOneWeek   /   7; 
if   (daysOutOneWeek   %   7   !=   0) 
weeks   ++; 

return   weeks   +   1; 
} 
} 

http://blog.csdn.net/letian_fly/article/details/2739618

方法一：

private int WeekOfYear(string date)
{
DateTime curDay = Convert.ToDateTime(date);

int firstdayofweek = Convert.ToInt32(Convert.ToDateTime(curDay.Year.ToString() + "- " + "1-1 ").DayOfWeek);

int days = curDay.DayOfYear;
int daysOutOneWeek = days - (7 - firstdayofweek);

if (daysOutOneWeek <= 0)
{
return 1;
}
else
{
int weeks = daysOutOneWeek / 7;
if (daysOutOneWeek % 7 != 0)
weeks ++;

return weeks + 1;
}
}

方法二：

System.Globalization.GregorianCalendar gc = new System.Globalization.GregorianCalendar();
int weekOfYear = gc.GetWeekOfYear(DateTime.Now, System.Globalization.CalendarWeekRule.FirstDay, DayOfWeek.Monday);

dt.DayOfYear/7