您必须订阅@Published属性 Package ，因此使用.onReceive(。
为了让事情更清楚，这里有一个带注解的小例子：

class MessageViewModel: ObservableObject{
    @Published var users = [String]()
    func fetchConvos() {
        self.users = ["Name 1", "Name 2"]
    }
}
struct ContentView: View {
    @ObservedObject var viewModel = MessageViewModel()
    
    @State var name: String = ""
    
    var body: some View {
        Text(name)
            // onReceice is to subscribe to @Published property wrappers
            .onReceive(viewModel.$users, perform: { users in
                name = users.first ?? "No users!"
            })
            .onAppear { // when the view appears we creating our users in the model, thanks our onReceive subscription, we can adapt our views justs by changing the @State property wrapper
                viewModel.fetchConvos()
            }
        
        // This button changes the view itself
        Button {
            changeName()
        } label: {
            Label("Give the user a new name", systemImage: "plus")
        }
        .buttonStyle(.bordered)
        
        // onChange is for subscribing to @State property wrappers
        .onChange(of: name) { newValue in
            let newName = newValue
            print("new user name:", newName)
            viewModel.users[0] = newName // here we notify the model, that the view changed
            #warning("Make sure the users array is not empty")
        }

    }
    func changeName() {
        name = "New name"
    }
}