This is an explanation about using Aggregate on a Fluent API such as Linq Sorting.
var list = new List<Student>();
var sorted = list
.OrderBy(s => s.LastName)
.ThenBy(s => s.FirstName)
.ThenBy(s => s.Age)
.ThenBy(s => s.Grading)
.ThenBy(s => s.TotalCourses);
and lets see we want to implement a sort function that take a set of fields, this is very easy using Aggregate instead of a for-loop, like this:
public static IOrderedEnumerable<Student> MySort(
this List<Student> list,
params Func<Student, object>[] fields)
{
var firstField = fields.First();
var otherFields = fields.Skip(1);
var init = list.OrderBy(firstField);
return otherFields.Skip(1).Aggregate(init, (resultList, current) => resultList.ThenBy(current));
}
And we can use it like this:
var sorted = list.MySort(
s => s.LastName,
s => s.FirstName,
s => s.Age,
s => s.Grading,
s => s.TotalCourses);