Question

I have a list of objects with the following properties:
RoomName, Date, StartTime, EndTime.

I want to get a result of total hours for each Roomname, this is calulated as EndTime-StartTime.

If i have a list as:

room1 12/2/2012 11.0 12.0
room1 12/2/2012 13.0 15.0
room2 12/3/2012 11.0 12.0

When i send room1 to LINQ query i want the answer as (12.0-11.0)+(15.0-13.0) which is 3.
How can I do this using a LINQ expression?

Answer 1

I believe this will do grouping and calculation

var query = from r in rooms
            group by r.RoomName into g
            select new {
                RoomName = g.Key,
                TotalHours = g.Sum(x => x.EndTime-x.StartTime)
            };

Thus you store start and end time as floating-point numbers, you can simply subtract them and do calculation.