How can I determine the week number of a certain date?

Question

I\'m trying to make a calendar using wpf. By using itemsPanel and more, I have a grid with 7 columns(sunday-saturday) and 6 rows(week# of month). If i can find the starting

Answer 1

You can use Calendar.GetWeekOfYear from Globalization to do this.

Here's the MSDN docs for it: http://msdn.microsoft.com/en-us/library/system.globalization.calendar.getweekofyear.aspx

You should pass the appropriate culture properties from CultureInfo.CurrentCulture to GetWeekOfYear so that you match the current culture properly.

Example:

int GetWeekOfYear(DateTime date)
{
    return Calendar.GetWeekOfYear(
        date,
        CultureInfo.CurrentCulture.DateTimeFormat.CalendarWeekRule,
        CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek
    );
}

You could easily modify this into an extension method on DateTime:

static int GetWeekOfYear(this DateTime date)
{
    return Calendar.GetWeekOfYear(
        date,
        CultureInfo.CurrentCulture.DateTimeFormat.CalendarWeekRule,
        CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek
    );
}