Question

I have a problem with this query trying to get a sum and a single value from the same child

Class 1

class Project{
    public int Id { get; set; }
    public string Name { get; set; }
    public IEnumerable<SubProject> SubProjects { get; set; }
}

Class 2

class SubProject{
    public int Id { get; set; }
    public string Description { get; set; }
    public IEnumerable<Week> Weeks { get; set; }
}

Class 3

class Week{
    public int Week { get; set; }
    public int Hours { get; set; }
}

what i’m trying to do is get all weeks, within a range, for a Project in a new list of classes like this

class ProjectOverview{
    public int Id { get; set; }
    public string Name { get; set; }
    public IEnumerable<ProjectWeekOverview> Weeks { get; set; }
}
class ProjectWeekOverview{
    public int Week { get; set; }
    public int TotalHours { get; set; }
}

i have tried something like this, but i cant manage to get in the week for it also, if what i done this far is even correct

List<Project> projects = { List.Of.Projects };
List<ProjectOverview> overview = projects
    .Select(p => new ProjectOverview
    {
        Id = p.Id,
        Name = p.Name,
        Weeks = p
            .SubProjects
            .Select(sp => new ProjectWeekOverview
            {
                Week = ????,
                TotalHours = sp
                    .Where(w => w.Week >= 30 && w.Week <= 35)
                    .Sum(w => w.Hours)
            })
    })
    .ToList();

anyone that can help with this?

Edit: a subproject can contain multiple week items with the same week like, to store hours from different action how long they took

week { week = 10, hours = 3 }
week { week = 10, hours = 4 }
week { week = 11, hours = 3 }

so what i want is to have the week property to a set week, and the totalhours to sum of all hours in that week

Answer 1

You need to GroupBy week, and have Week as the key and Sum as item.

Give this a try. The output is an anonymous type, must have to convert it to whatever type you want as result. Its the grouping that matters.

        List<Project> projects = null;

        var weeksAndHours = projects
            .Select(p => new 
            {
                Id = p.Id,
                Name = p.Name,
                Weeks = p
                    .SubProjects.SelectMany(sp => sp.Weeks)
                    .Where(w => w.Week >= 30 && w.Week <= 35)
                    .GroupBy(w => w.Week)
                    .Select(g => new { week = g.Key, hours = g.Sum( w=> w.Hours) })
            });