ForEach未使用动态内容SwiftUI正确更新

struct ListTimeCodeView: View {
    
    @ObservedObject var timeCodeListVM: TimeCodeListViewModel
    @State var presentEditTimeCode: Bool = false
    @State var timeCodeEdit: TimeCodeViewModel?

    init() {
        self.timeCodeListVM = TimeCodeListViewModel()
    }

    var body: some View {
        VStack {
            HStack {
                Text("TimeCodes Reduced by Favorite:")
                Text("(self.timeCodeListVM.timeCodes.reduce(into: "") {$0 += $1.isFavorite ? "F" : "N"})")
            }

            List {
                ForEach(self.timeCodeListVM.timeCodes) { timeCode in
                        
                   TimeCodeDetailsCell(fullName: timeCode.fullName, abbreviation: timeCode.abbreviation, color: timeCode.color, isFavorite: timeCode.isFavorite, presentEditTimeCode: $presentEditTimeCode)
                        .contentShape(Rectangle())
                        .onTapGesture {
                            timeCodeEdit = timeCode
                                
                        }
                        .sheet(item: $timeCodeEdit, onDismiss: didDismiss) { detail in
                            EditCodeView(timeCodeEdit: detail)   
                        }
                }    
            }
        }
    }      
}

class TimeCodeListViewModel: ObservableObject {
    
    @Published var timeCodes = [TimeCodeViewModel]()
    
    init() {
        fetchAllTimeCodes()
    }

    func fetchAllTimeCodes() {
        self.timeCodes = CoreDataManager.shared.getAllTimeCodes().map(TimeCodeViewModel.init)
    } 
}


class TimeCodeViewModel: Identifiable {
    var id: String = ""
    var fullName = ""
    var abbreviation = ""
    var color = ""
    var isFavorite = false
    var tags = ""

    
    init(timeCode: TimeCode) {
        self.id = timeCode.id!.uuidString
        self.fullName = timeCode.fullName!
        self.abbreviation = timeCode.abbreviation!
        self.color = timeCode.color!
        self.isFavorite = timeCode.isFavorite
        self.tags = timeCode.tags!
    }
}

var hoursTimeCode: [[TimeCodeCellViewModel]] = []

// initialize hoursTimeCode

VStack(spacing: 3) {
   ForEach(self.hoursTimeCode, id: .self) {row in
      HStack(spacing: 3){
         HourTimeCodeCell(date: row[0].date) // cell view for hour
            .frame(minWidth: 50)
         ForEach(row.indices, id: .self) {cell in
            // TimeCodeBlockCell displays minutes normally. If it is selected, and a button is pressed, it is assigned a TimeCode which it will then display
            TimeCodeBlockCell(timeCodeCellVM: row[cell], selectedArray: $selectedTimeCodeCells)
               .frame(maxWidth: .infinity)
               .aspectRatio(1.0, contentMode: .fill)
         }
      }                              
   }                          
}

class TimeCodeCellViewModel:Identifiable, Hashable {
    static func == (lhs: TimeCodeCellViewModel, rhs: TimeCodeCellViewModel) -> Bool {
        if lhs.id == rhs.id {
            return true
        }
        else {
            return false
        }
    }

    func hash(into hasher: inout Hasher) {
        hasher.combine(id)
        hasher.combine(isSet)
        hasher.combine(timeCode)
        hasher.combine(date)
    }

    var id: String = ""
    var date = Date()
    var isSet = false
    var timeCode: TimeCode
    
    var frame: CGRect = .zero
    
    init(timeCodeCell: TimeCodeCell) {
        self.id = timeCodeCell.id!.uuidString
        self.date = timeCodeCell.date!
        self.isSet = timeCodeCell.isSet
        self.timeCode = timeCodeCell.toTimeCode!
    }
}

struct EditCodeView:View{
    @EnvironmentObject var timeCodeListVM: TimeCodeListViewModel
    //This will observe changes to the view model
    @ObservedObject var timeCodeViewModel: TimeCodeViewModel
    var body: some View{
        EditTimeCodeView(timeCode: timeCodeViewModel.timeCode)
            .onDisappear(perform: {
                //*********TO SEE CHANGES WHEN YOU EDIT
                //uncomment this line***********
                //_ = timeCodeListVM.update(timeCodeVM: timeCodeViewModel)
            })
    }
}
struct EditTimeCodeView: View{
    //This will observe changes to the core data entity
    @ObservedObject var timeCode: TimeCode
    var body: some View{
        Form{
            TextField("name", text: $timeCode.fullName.bound)
            TextField("appreviation", text: $timeCode.abbreviation.bound)
            Toggle("favorite", isOn: $timeCode.isFavorite)
        }
    }
}
class TimeCodeListViewModel: ObservableObject {
    //Replacing this whole thing with a @FetchRequest would be way more efficient than these extra view models
    //IF you dont want to use @FetchRequest the only other way to observe the persistent store for changes is with NSFetchedResultsController
    //https://stackoverflow.com/questions/67526427/swift-fetchrequest-custom-sorting-function/67527134#67527134
    //This array will not see changes to the variables of the ObservableObjects
    @Published var timeCodeVMs = [TimeCodeViewModel]()
    private var persistenceManager = TimeCodePersistenceManager()
    init() {
        fetchAllTimeCodes()
    }
    
    func fetchAllTimeCodes() {
        //This method does not observe for new and or deleted timecodes. It is a one time thing
        self.timeCodeVMs = persistenceManager.retrieveObjects(sortDescriptors: nil, predicate: nil).map({
            //Pass the whole object there isnt a point to just passing the variables
            //But the way you had it broke the connection
            TimeCodeViewModel(timeCode: $0)
        })
    }
    
    func addNew() -> TimeCodeViewModel{
        let item = TimeCodeViewModel(timeCode: persistenceManager.addSample())
        timeCodeVMs.append(item)
        //will refresh view because there is a change in count
        return item
    }
    ///Call this to save changes
    func update(timeCodeVM: TimeCodeViewModel) -> Bool{
        let result = persistenceManager.updateObject(object: timeCodeVM.timeCode)
        //You have to call this to see changes at the list level
        objectWillChange.send()
        return result
    }
}

//DO you have special code that you aren't including? If not what is the point of this view model?
class TimeCodeViewModel: Identifiable, ObservableObject {
    //Simplify this
    //This is a CoreData object therefore an ObservableObject it needs an @ObservedObject in a View so changes can be seem
    @Published var timeCode: TimeCode
    init(timeCode: TimeCode) {
        self.timeCode = timeCode
    }
}