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How to access a Core Data managed object context from a SwiftUI view

Paul Hudson    @twostraws   

Updated for Xcode 12.0

If you followed my Core Data and SwiftUI set up instructions, you’ve already injected your managed object context into the SwiftUI environment.

If not, make sure you add this code to your scene delegate:

guard let context = (UIApplication.shared.delegate as? AppDelegate)?.persistentContainer.viewContext else {
    fatalError("Unable to read managed object context.")
}

window.rootViewController = UIHostingController(rootView: ContentView().environment(\.managedObjectContext, context))

That passes our view context directly into ContentView as environment data, which means we can add an @Environment property to ContentView to read the managed object context right out:

@Environment(\.managedObjectContext) var managedObjectContext

Note: Adding a local property for the managed object context isn’t required for performing fetch requests using @FetchRequest – you only need it for saving, deleting, and some other tasks.

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