Question

I have a list of Func defining an ordering:

var ordering = new List<Func<Person, IComparable>> 
                 { x => x.Surname, x => x.FirstName };

I can order the results with something like…

people = people.OrderBy(ordering[0]).ThenBy(ordering[1]);

I’m trying to figure how to do the above when the list can contain any number of sequential orderings. Is it possible?

Answer 1

people = people.OrderBy(ordering[0]).ThenBy(ordering[1]).ThenBy(ordering[2]);

is the same as

var orderedPeople = people.OrderBy(ordering[0]);
orderedPeople = orderedPeople.ThenBy(ordering[1]);
orderedPeople = orderedPeople.ThenBy(ordering[2]);
people = orderedPeople;

so you simply write a loop like this:

if (ordering.Count != 0)
{
    var orderedPeople = people.OrderBy(ordering[0]);
    for (int i = 1; i < ordering.Count; i++)
    {
        orderedPeople = orderedPeople.ThenBy(ordering[i]);
    }
    people = orderedPeople;
}