Hello! I successfully made a generic fetchRequest like Paul is showing in Dynamically filtering @FetchRequest with SwiftUI - CoreData SwiftUI Tutorial 6/7. All is working absolute fine but i cannot implement the .onDelete modifier. Does anyone have a solution for that? Please find my code below. Thanks a lot in advance! Martin

My FetchRequest View:

import CoreData
import SwiftUI

struct FetchedListView<T: NSManagedObject, Content: View>: View {
    @FetchRequest var fetchRequest: FetchedResults<T>
    let content: (T) -> Content

    var body: some View {
        List(fetchRequest, id: \.self) { item in
            self.content(item)
        }
    }

    init(filterKey: String, filterValue: String, sortingKey: String, sortAscending: Bool, @ViewBuilder content: @escaping (T) -> Content) {
        _fetchRequest = FetchRequest<T>(sortDescriptors: [NSSortDescriptor(key: sortingKey, ascending: sortAscending)], predicate: filterValue == "" ? nil : NSPredicate(format: "%K BEGINSWITH[c] %@", filterKey, filterValue))
        self.content = content
    }
}

My Content View:

struct ContentView: View {

    @EnvironmentObject var data:  DataController
    @Environment(\.managedObjectContext) var moc

//    @FetchRequest(sortDescriptors: [
//        SortDescriptor(\.title),
//        SortDescriptor(\.author)
//    ]) var books: FetchedResults<Book>
//    
//    @State var sortDescriptor: NSSortDescriptor = NSSortDescriptor(keyPath: \Book.title, ascending: true)
    @State private var sortKey = "title"
    @State private var ascent = true
    @State private var filterKey = "title"

    @State private var sortType: Int = 0
    @State private var showingAddScreen = false

    enum Sort: String {
        case title, author
    }
    enum Filter: String {
        case title, author, genre
    }
    var body: some View {

        NavigationView {
            FetchedListView(filterKey: filterKey, filterValue: "", sortingKey: sortKey, sortAscending: ascent, content: { (book: Book) in
                NavigationLink {
                    DetailView(book: book)
                } label: {
                    HStack {
                        EmojiRatingView(rating: book.rating)
                            .font(.largeTitle)

                        VStack(alignment: .leading) {
                            Text(book.title ?? "Unknown Title")
                                .font(.headline)
                            Text(book.author ?? "Unknown Author")
                                .foregroundColor(.secondary)
                        }
                    }
                }
            })
            .navigationTitle("Bookworm")
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    EditButton()
                }
                ToolbarItem(placement: .principal) {
                    VStack(alignment: .center) {

                        Menu {
                            Button {
                                sortKey =  Sort.title.rawValue
                                ascent = true
                            } label: {
                                Label("Title", systemImage: "arrow.down")
                            }
                            Button {
                                sortKey =  Sort.title.rawValue
                                ascent = false
                            } label: {
                                Label("Title", systemImage: "arrow.up")
                            }
                            Button("Author") {
                                sortKey = Sort.author.rawValue
                            }
                            Button("Author") {
                                sortKey = Sort.author.rawValue
                            }
                        } label: {
                            Label("Sort", systemImage: "filemenu.and.cursorarrow")
                        }
                    }
                }
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button {
                        showingAddScreen.toggle()
                    } label: {
                        Label("Add Book", systemImage: "plus")
                    }
                }
            }
            .sheet(isPresented: $showingAddScreen) {
                AddBookView()
            }

        }
    }
//    func deleteBooks(at offsets: IndexSet) {
//        for offset in offsets {
//            let book = books[offset]
//            moc.delete(book)
//        }
//
//        //        //        try? moc.save()
//    }
}

I guess your .onDelete should be added on the list i.e.

List(fetchRequest, id: \.self) { item in
            self.content(item)
        }.onDelete(perform: deleteBooks)

Or try like this..

List(fetchRequest, id: \.self) { item in
            self.content(item).onDelete(perform: deleteBooks)
        }

the deleteBooks func should be in the struct FetchedListView and as below:

func deleteBooks(at offsets: IndexSet) {
        for offset in offsets {
            let item = fetchRequest[offset]
            moc.delete(item)
        }
        try? moc.save()
    }

You should add also the below in the FetchedList View file

@Environment(\.managedObjectContext) var moc

Give it a try..

...thanks @Bnerd, unfortunatly it's not working. I triggers following error:

Value of type 'Content' has no member 'onDelete'

or

Value of type 'List<Never, ForEach<FetchedResults<T>, Fetchedesults<T>.Element Content>>' (aka 'List<Never, ForEach<FetchedResults<T>, T, Content>>') has no member 'onDelete'

Ok change it to the below:

List {
ForEach(fetchRequest, id: \.self) { item in
            self.content(item)
        }.onDelete(perform: deleteBooks)
}