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

this piece of code keep making error. :

unable create constant value of type 'repository.dbmodel.subscriber'. primitive types or enumeration types supported in context.

i've changed few times keeps coming error.

using (subscriberdbhandler db = new subscriberdbhandler()) {     ienumerable <subscriber> newsubscribers = subscribers                                               .where(sub => db.subscriber                                               .any(asub => !asub.email.equals(sub.email)));     list<subscriber> updatesubscribers = db.subscriber                                            .where(dbsub => subscribers                                            .any(lsub => lsub.email                                            .equals(dbsub.email))).tolist();     if(newsubscribers.count() >= 1)     {         db.subscriber.addrange(newsubscribers);     }     updatesubscribers.foreach(asub => asub.state = subscribers                                                   .firstordefault(sub => sub.email                                                   .equals(asub.email)).state ?? "error" );     db.savechanges(); } 

i'd appreciate if point out error or come more efficient way this.

in advance time , help.

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i know there few post error out there when reading them can't figure out how relate problem. i'm sorry if common mistake , others have provided solution

the object subscribers list<subscriber>

i don't seem able find line but. stack trace contain this.

at system.linq.enumerable.tolist[tsource](ienumerable1 source) @ repository.subscribrepository.addorupdatesubscribers(list1 subscribers)

you use local collection, subscribers, directly in linq statement. these objects can't translated sql. there mappings primitive types database types.

i'd suggest use

var emails = subscribers.select(s => s.email).tolist(); 

and proceed 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();