Ios 从视图模型中更新 EnvironmentObject

在SwiftUI中，我希望将环境对象传递给视图模型，以便可以更改/更新它.EnvironmentObject是一个简单的AppState，由单个属性计数器组成.

class AppState: ObservableObject {
    @Published var counter: Int = 0 
}

视图模型"CounterViewModel"更新环境对象，如下所示:

class CounterViewModel: ObservableObject {
    
    var appState: AppState
    
    init(appState: AppState) {
        self.appState = appState
    }
    
    var counter: Int {
        appState.counter 
    }
    
    func increment() {
        appState.counter += 1
    }
    
}

ContentView显示值:

struct ContentView: View {
    
    @ObservedObject var counterVM: CounterViewModel
    
    init(counterVM: CounterViewModel) {
        self.counterVM = counterVM
    }
    
    var body: some View {
        VStack {
            Text("\(counterVM.counter)")
            Button("Increment") {
                counterVM.increment()
            }
        }
        
    }
}

我也正在注入状态，如下所示:

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        NavigationStack {
            
            let appState = AppState()
            
            ContentView(counterVM: CounterViewModel(appState: appState))
                .environmentObject(appState)
        }
    }
}

问题是，当我单击增量按钮时，计数器VM.计数器从不返回更新后的值.我错过了什么？