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Day 58: cannot get the results sorted into sections automatically

Forums > 100 Days of SwiftUI

Hi all,

Following along with the tutorial, I did not manage to get the result shown in the video. The view shows separate sections for all the candies.

To make the code work (even without the automatic sorting), I needed to follow the example of @rastazion23 and add a Persistence.swift file with code:

import CoreData

struct PersistenceController {
    static let shared = PersistenceController()

    let container: NSPersistentContainer

    init() {
        container = NSPersistentContainer(name: "CoreDataProject")

        container.loadPersistentStores{ (storeDescription, error) in
            if let error = error as NSError? {
                fatalError("Unresolve Error: \(error)")

(source: https://www.hackingwithswift.com/forums/100-days-of-swiftui/day-54-bookworm-an-nsmanagedobject-of-class-book-must-have-a-valid-nsentitydescription/5043 on this same Forum)

This includes adding reference to the CoreDataProjectApp.swift file:

import SwiftUI

struct CoreDataProjectApp: App {
    let persistenceContainer = PersistenceController.shared

    var body: some Scene {
        WindowGroup {
                .environment(\.managedObjectContext, persistenceContainer.container.viewContext)

As well as using the tip highlighted at the end of the lesson, in adding .mergeByPropertyObjectTrump in DataController.swift:

import CoreData
import Foundation

class DataController: ObservableObject {
    let container = NSPersistentContainer(name: "CoreDataProject")

    init() {
        container.loadPersistentStores { description, error  in
            if let error = error {
                print("Core Data failed to load: \(error.localizedDescription)")
            self.container.viewContext.mergePolicy = NSMergePolicy.mergeByPropertyObjectTrump 

That being said, I still do not get the automatically sorted result. Not posting the ContentView.swift code as it is identical to the one in the video / description. Does anybody else have the same issue, and would anybody be able to explain to me what I'm doing wrong here?


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