Orderby() in tri-level entity structure - linq

Question

I have 3 entities that all encompass eachother. MakeSource can have many ModelSources and ModelSources can have many YearSources. The data I am retrieving looks like this:
So far I can only order by Makes and not models or years.
var data = context.MakeSources.OrderBy(P => P.Name).Include(A => A.ModelSources
.Select(B => B.YearSources));
Placing more OrderBy calls within the include throws errors. My question is:
How can I get a neatly ordered collection of first Makes ordered by asc, for each make its models ordered by ascending and for each model its years ordered by ascending?
I tried using ThenBy() but then I cannot access nested properties of ModelSource
var data = context.MakeSources.Include(A => A.ModelSources
.Select(B => B.YearSources)).OrderBy(P => P.Name).ThenBy(p => p.ModelSources.

Answer 1

I re-created your situation in my sandbox database, and wrote a linq query like this. This gives you a list of makes, models, and years. I used cars, but i really don't know what your data looks like.
var data = (from a in ctx.MakeSources
join b in ctx.ModelSources on a.Id equals b.MakeSourceId
join c in ctx.YearSources on b.Id equals c.ModelSourceId
orderby a.Name, b.Name, c.Year
select new { Make = a.Name, Model = b.Name, Year = c.Year }).ToArray();
This will give you a flat list
To order them in collections, such as each make has a collection of models, and models have a collection of years, I did this.
var data = (from a in ctx.MakeSources
orderby a.Name
select new
{
Make = a.Name,
Models = (from b in ctx.ModelSources
where b.MakeSourceId == a.Id
orderby b.Name
select new
{
Model = b.Name,
Years = (from c in ctx.YearSources
where c.ModelSourceId == b.Id
orderby c.Year
select new { ModelYear = c.Year })
})
}).ToArray();
I am not aware of any easy way to do it using just includes and .OrderBy()s as it preloads the navigation properties, and the result in the include method has to be a collection of entities, as far as I am aware. So returning an ordered list won't load the entities (as evident by the error you received)