How to get Count of value of nested object by linq [closed]

Question

Can anyone please suggest how to get the sum of points from all the Event objects by using linq.

new Category
{
     CategoryId = "NUTR",
     CategoryName = "NUTR",
     CategoryDescription = "NUTR Desc",
     TotalPoints = "100",
     Events = new List<Event>
           {
             new Event{Firstname = "HELEN",Surname = "BECKETT", 
                 Points = "10", Description = "NUTR Desc",Eventdate = "2013/04/19",EntityNumber = "1203206956"},
             new Event{Firstname = "PAUL",Surname = "BECKETT", 
                 Points = "90", Description = "NUTR Desc",Eventdate = "2013/06/19",EntityNumber = "1203206957"}
           }
}

Answer 1

You need to use SelectMany to flatten the list of events, then do the sum:

var totalPoints = categories
    .SelectMany(c => c.Events)
    .Sum(e => Convert.ToInt32(e.Points));