SwiftUI-在“onAppear”中更改属性时,不会更改工作表

options.categories 在一个 List .

选项.类别 ContentView onAppear ,工作表不反映更改。这还是一张空名单。

struct ViewOptions {
    public var categories = [String]()
}
struct ContentView: View {
    @State var presentingModal = false
    @State var options = ViewOptions()

    var body: some View {
        VStack {
            Text("Tap to present:")
            Button("Present") { presentingModal = true } /// set presentingModal to true, to present the sheet
            .sheet(isPresented: $presentingModal) {
                ModalView(options: options)
            }
        }
        .onAppear {
            options.categories = ["one", "two", "three", "four"]
        }
    }
}

struct ModalView: View {
    var options: ViewOptions
    var body: some View {
        List { /// display options.categories in a List
            ForEach(options.categories, id: \.self) { word in
                Text(word)
            }
        }
    }
}

结果(没有显示!):

.sheet 只是嵌入 ModalView ,它起作用了。

VStack {
    Text("Tap to present:")
       Button("Present") { presentingModal = true }
//     .sheet(isPresented: $presentingModal) { /// get rid of the sheet
           ModalView(options: options)
//     }
}
.onAppear {
    options.categories = ["one", "two", "three", "four"]
}

如何继续使用工作表,但在更改值时更新列表?