Attaches the given entity to the context underlying the set. That is, the entity is placed into the context in the Unchanged state, just as if it had been read from the database.
public virtual TEntity Attach (TEntity entity);
abstract member Attach : 'Entity -> 'Entity override this.Attach : 'Entity -> 'Entity
Public Overridable Function Attach (entity As TEntity) As TEntity
The entity to attach.
Attach is used to repopulate a context with an entity that is known to already exist in the database.
SaveChanges will therefore not attempt to insert an attached entity into the database because
it is assumed to already be there.
Note that entities that are already in the context in some other state will have their state set
to Unchanged. Attach is a no-op if the entity is already in the context in the Unchanged state.