Swift CoreData: Unrecognised Selector sent to Instance - swift

Question

I am implementing Swift CoreData into my application, However I continue to face the error 'Unrecognised selector sent to Instance' when adding data to the class set up as you can see below. I realise that this is probably a rookie error, so thanks for your patience.
func coreDataRequest(){
container = NSPersistentContainer(name: "tileData")
container.loadPersistentStores { StoreDescription, error in
if let error = error {
print("Unresolved Error \(error)")
}
}
var campaign = Campaign()
campaign.countryName = "France"
}
The Error
unrecognized selector sent to instance
Here is my XCDataModel

Answer 1

Have you generate Campaign() class, that you add to tileData.xcdatamodeld?
if so create a NSManagedObjectContext like this:
var context: NSManagedObjectContext = {
return persistentContainer.viewContext
}()
and then use it to create Campaign like this:
var campaign = Campaign(context: context)
campaign.countryName = "France"
then if you want to store your object you have to call save on the context:
func saveContext () {
if context.hasChanges {
do {
try context.save()
} catch {
context.rollback()
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
}
}
I recommend you to look through few tutorials, it would save your time in future. There are a lot of them, just google it.

Answer 2

Without seeing all your code its difficult to say what is wrong, just from what I can see the container is missing a "let" in-front unless that was declared outside the function. This is a really good tutorial on setting up and using CoreData https://www.raywenderlich.com/books/core-data-by-tutorials/v7.0/chapters/3-the-core-data-stack#toc-chapter-006-anchor-011