I a portion of my EF model that looks like this:
Summary:
- Location has many Posts
- Post is an abstract class
- Discussion derives from Post
- Discussions have many Comments
Now, the query i'm trying to achieve:
Get information about Location Id 1234, including any Discussions and Comments associated with those Discussions.
I can get discussions and the comments like this:
var discussions = ctx.Posts
.OfType<Discussion>()
.Include(x => x.Comments)
.ToList();
But i can't seem to get it based on the Posts navigation on the Location entity.
I've tried this:
var locationWithDiscussionsAndComments = ctx
.Locations
.Include(x => x.Posts
.OfType<Discussion>()
.Select(y => y.Comments))
.SingleOrDefault();
Which compiles, but i get the error:
System.ArgumentException: The include path expression must refer to a property defined by the entity, optionally also with nested properties or calls to Select.
Parameter name: path
Any ideas? I could probably go "backwards" from the Posts:
var locationWithDiscussionsAndComments = ctx
.Posts
.Include(x => x.Location)
.OfType<Discussion>()
.Include(x => x.Comments)
.Where(x => x.LocationId == 1234)
.Select(x => x.Location)
.ToList();
But that is both hairy and semantically wrong in terms of my repositories (i shouldn't have to go through a post repository to get information about a location).
Any ideas?
EDIT
So after having a bigger think about it, i realized that OfType<T>
is a filter operation. As as we know, EF does not support filtering with eager loading. The only options are retrieving everything, or using anonymous type projection.
No way i can retrieve everything, as there is far too much meta data involved. So i'm attempting the anonymous type projection.
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