Error: Only primitive types or enumeration types are supported in this context EF

Question

This piece of code keep making this error. :

Unable to create a constant value of type \'Repository.DBModel.Subscriber\'. Only primitive types or enum

Answer 1

You use a local collection, Subscribers, directly in a LINQ statement. But these objects can't be translated into SQL. There are only mappings from primitive types to database types.

I'd suggest you use

var emails = Subscribers.Select(s => s.Email).ToList();

And proceed by using these strings (i.e. primitive values) in Contains statements like:

var newSubscribers = db.Subscriber
                       .Where(dbSub => !emails.Contains(dbSub.Email))
                       .ToList();
var updateSubscribers = db.Subscriber
                          .Where(dbSub => emails.Contains(dbSub.Email))
                          .ToList();

Answer 2

Changing updateSubscribers to an IEnumerable will prevent this error