Question

Having a date reference UserJoinDate and the list of dates List friendsJoined I would like to count how many friends joined a service before UserJoinDate and how many as the same time or later.

I wrote the following lines but it doesn’t work:

List<DateTime> joinersDates = getJoinersDates();
FriendsJoinedBeforeCount = joinersDates .Where(x => x < UserJoinDate).Count();
FriendsJoinedAfterCount = joinersDates .Where(x => x >= UserJoinDate).Count();

Does anyone know how to count how many dates from the list joinersDates are before UserJoinDate and how many the same or after?

Edit

Here is the Copy from ImmediateWindow:

churnersDates.Count( x => x > UserChurnDate)
Expression cannot contain lambda expressions

UserJoinDate Is DateTime

Example:

UserJoinDate = 9.11.2010 0:30:00

(the value is copied from Date: {9.11.2010 0:00:00}
Day: 9
DayOfWeek: Tuesday
DayOfYear: 313…)

and

joinersDates.First() = 17.5.2011 0:30:00

Thanks!

Answer 1

Try the following code:

List<DateTime> joinersDates = getJoinersDates();
FriendsJoinedBeforeCount = joinersDates.Count(x => x.ToUniversalTime() < UserJoinDate.ToUniversalTime());
FriendsJoinedAfterCount = joinersDates.Count - FriendsJoinedBeforeCount ;

Or try to use Ticks property:

List<DateTime> joinersDates = getJoinersDates();
FriendsJoinedBeforeCount = joinersDates.Count(x => x.ToUniversalTime().Ticks < UserJoinDate.ToUniversalTime().Ticks);
FriendsJoinedAfterCount = joinersDates.Count - FriendsJoinedBeforeCount ;