Discussion :

[mischa]

Bonjour,

est ce que quelqu'un connaitrait un script pour calculer le numéro d'une semaine donnée en parametre (sans les bugs!) ??

[guitoux1]

Tu peux trouver ça avec la méthode GetWeekOfYear() de l'objet Calendar :

Code :

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System.Globalization.GregorianCalendar cal = new System.Globalization.GregorianCalendar(System.Globalization.GregorianCalendarTypes.Localized);
int week = cal.GetWeekOfYear(DateTime.Now, System.Globalization.CalendarWeekRule.FirstDay, DayOfWeek.Monday);

A utiliser avec le calendrier qui va bien (ici grégorien) et selon la culture. Par contre je suis pas certian du second paramètre (CalendarWeekRule.FirstDay)

[guitoux1]

Selon Wikipédia (http://fr.wikipedia.org/wiki/ISO_860...9ro_de_semaine), la semaine 1 est celle qui contient le premier jeudi de l'année. Autrement dit, la semaine qui possède au moins 4 jours dans la nouvelle année. Du coup, le bon code est :

Code :

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System.Globalization.GregorianCalendar cal = new System.Globalization.GregorianCalendar(System.Globalization.GregorianCalendarTypes.Localized);
int week = cal.GetWeekOfYear(DateTime.Now, System.Globalization.CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);

[mischa]

J'ai trouvé ca qui marche bien et sans bug du 1er janvier et du 31 decembre

private static int WeekNumber_Entire4DayWeekRule(DateTime date)
{
// Updated 2004.09.27. Cleaned the code and fixed a bug.
// Compared the algorithm with code published here .
// Tested code successfully against the other algorithm
// for all dates in all years between 1900 and 2100.
// Thanks to Marcus Dahlberg for pointing out the deficient logic.

// Calculates the ISO 8601 Week Number
// In this scenario the first day of the week is monday,
// and the week rule states that:
// [...] the first calendar week of a year is the one
// that includes the first Thursday of that year and
// [...] the last calendar week of a calendar year is
// the week immediately preceding the first
// calendar week of the next year.
// The first week of the year may thus start in the
// preceding year

const int JAN = 1;
const int DEC = 12;
const int LASTDAYOFDEC = 31;
const int FIRSTDAYOFJAN = 1;
const int THURSDAY = 4;
bool ThursdayFlag = false;

// Get the day number since the beginning of the year
int DayOfYear = date.DayOfYear;

// Get the numeric weekday of the first day of the
// year (using sunday as FirstDay)
int StartWeekDayOfYear =
(int)(new DateTime(date.Year, JAN, FIRSTDAYOFJAN)).DayOfWeek;
int EndWeekDayOfYear =
(int)(new DateTime(date.Year, DEC, LASTDAYOFDEC)).DayOfWeek;

// Compensate for the fact that we are using monday
// as the first day of the week
if (StartWeekDayOfYear == 0)
StartWeekDayOfYear = 7;
if (EndWeekDayOfYear == 0)
EndWeekDayOfYear = 7;

// Calculate the number of days in the first and last week
int DaysInFirstWeek = 8 - (StartWeekDayOfYear);
int DaysInLastWeek = 8 - (EndWeekDayOfYear);

// If the year either starts or ends on a thursday
// it will have a 53rd week
if (StartWeekDayOfYear == THURSDAY || EndWeekDayOfYear ==
THURSDAY)
ThursdayFlag = true;

// We begin by calculating the number of FULL weeks
// between the start of the year and our date.
// The number is rounded up, so the smallest possible value is 0.
int FullWeeks = (int)Math.Ceiling((DayOfYear - (DaysInFirstWeek)) /
7.0);

int WeekNumber = FullWeeks;

// If the first week of the year has at least four days, then
// the actual week number for our date can be incremented by one.
if (DaysInFirstWeek >= THURSDAY)
WeekNumber = WeekNumber + 1;

// If week number is larger than week 52
// (and the year doesn't either start or end on a thursday)
// then the correct week number is 1.
if (WeekNumber > 52 && !ThursdayFlag)
WeekNumber = 1;

// If week number is still 0, it means that we are trying
// to evaluate the week number for a week that belongs
// in the previous year(since that week has 3 days or
// less in our date's year).
// We therefore make a recursive call using
// the last day of the previous year.
if (WeekNumber == 0)
WeekNumber = WeekNumber_Entire4DayWeekRule(
new DateTime(date.Year - 1, DEC, LASTDAYOFDEC));
return WeekNumber;
}

[mischa]

Merci en tout cas pour ton aide

[guitoux1]

OK. Juste que c'est la même chose, mais en 83 lignes de code au lieu de 2.
Bonne chance