Question

I am trying to get the week of a date from the database and compare it to a user selected value from a DateTimePicker. My users can select a day and I wrote a class that gives me the week of that day in the form 1 to 52. I am trying to select get LINQ to compare the weeks of a given date from the database to the week selected by the user. Example:

var report = (from orders in Context.Orders
              where DateEx.ISOWeekNumber(orders.Date) == 
                    DateEx.ISOWeekNumber(datepicker1.Value)
              select orders);

But it is not working at all as LINQ doesn’t have a translation for the ISOWeekNumber.
Anyone knows how I can do this?

Answer 1

What about something of the ilk?

Math.Truncate(date.DayOfYear/7) +1

Giving you:

var report = (from orders in Context.Orders
    where Math.Truncate(orders.Date.DayOfYear/7) + 1 ==
    Math.Truncate(datepicker1.Value.DayOfYear/7) + 1
    select orders);

Hope that helps,

Dan

Probably take Math.Truncate(date.DayOfYear/7) into your new DateEx class