Question

I’m trying to wrap the results of a query with a class called QueryResultViewModel from a list of dynamic objects retrieved by LINQ. These contain a integer field called Worked. I should not use a non-dynamic type because depending on the query it has other fields. I tried that:

    var query = new HoursQuery( .. parameters .. );
    this.Result = new ObservableCollection<QueryResultViewModel>(
      query.Execute().Select( x => new QueryResultViewModel( x.Worked )));

But I got “‘object’ does not contain a definition for ‘Worked'” and I don’t know If it can be fixed without changing query’s return type.

The Execute code may be useful too:

    var res = some_list.GroupBy(a => new { a.Employee, a.RelatedTask, a.Start.Month })
       .Select(g => new { K = g.Key, Worked = g.Sum(s => s.Duration.TotalHours) });

EDIT: This worked great but maybe it’s not very elegant.

    public class HQueryDTO
    {
        public double Worked;
        public object K;
    }

    public IEnumerable<dynamic> Execute()
    {
        var list = base.Execute();
        return res = list.GroupBy(a => new { a.Employee, a.RelatedTask } )
          .Select(g => new HQueryDTO { K = g.Key, Worked = g.Sum(s => s.Duration.TotalHours) });
    }

Now that the result has a type it can be returned dynamic.

Answer 1

I’m assuming you get that error at compile-time, in which case simply introduce dynamic via a cast:

.Select(x => new QueryResultViewModel( ((dynamic)x).Worked ))