In the last few posts we saw how to hide use of the join entity from two entities with a many-to-many relationship. This post doesn’t add any additional functionality, it just abstracts some of what we saw so it can be re-used more easily.
In the previous post we ended up with entities that hide the join entity from the public surface. However, it was not possible to add or removed entities through this public surface. To enable this we need an ICollection implementation that acts as a true facade over the real join entity collection and delegates all responsibilities to that collection.
As of EF Core 2.0, many-to-many relationships without an explicitly mapped join table are not supported. However, all is not lost. In this series of posts I will show:
- Mapping many-to-many relationships with a join entity/table
- Abstracting/hiding the join entity
- In a simple way for read-only access to the relationship
- In a more involved way that allows entities to be added and removed from each end