在快速UI中从另一个视图中排除模态视图

我想在SwiftUI中取消一个模态视图，但我就是不能

这是我的代码：

内容视图：

import SwiftUI

enum Destination {
    case modal
}

struct ContentView: View {
    @Environment(\.presentationMode) var presentationMode

    @State private var showModal = false

    var body: some View {
        NavigationView {
            ScrollView(.vertical, showsIndicators: false) {
                VStack{
                    SubscribeButtonView(buttonTitle: "Modal", destination: .modal, showModal: $showModal)
                            .padding(.top, 50)
                            .padding(.leading, 30)
                            .padding(.trailing, 30)
                    Spacer()
                }
            }
            .navigationBarTitle(Text("Menu"))
        }
    }
}

ModalView：

import SwiftUI

struct ModalView: View {
    @Environment(\.presentationMode) var presentationMode

    var body: some View {
        NavigationView {
            ScrollView(.vertical, showsIndicators: false) {
                    VStack(alignment: .leading) {
                     Spacer()
                        SaveButtonView(origin: .modal)
                        Spacer()
                    }
                    .padding(.leading, 20)
                    .padding(.trailing, 20)
            }
            .navigationBarTitle("Modal")
            .navigationBarItems(trailing: Button(action: {
                self.presentationMode.wrappedValue.dismiss()
            }) {
                Text("Cancel")
            })
        }
    }
}

SubscribeButtonView：

import SwiftUI

struct SubscribeButtonView: View {
    @Environment(\.presentationMode) var presentationMode

    var buttonTitle: String
    var destination: Destination

    @Binding var showModal: Bool

    var body: some View {
        Button(action: {
            self.showModal.toggle()
        }) {
            HStack {
                Image(systemName: "plus.circle")
                    .font(.body)
                Text(buttonTitle)
            }
        }.sheet(isPresented: $showModal) {
            if self.destination == .modal {
                ModalView()
            }
        }
        .padding()
    }
}

SaveButtonView：

import SwiftUI

struct SaveButtonView: View {
    @Environment(\.presentationMode) var presentationMode
    var origin: Destination

    var body: some View {
        Button(action: {
            //THIS IS NOT WORKING
            self.presentationMode.wrappedValue.dismiss()
        }) {
            HStack {
                Text("Save")
            }
        }
        .padding()
    }
}

我试着创建一个非常简单的新项目，只有一个状态来调用模式、菜单、模式和两个按钮，它工作得很好。我不明白为什么上面的代码不起作用

有人有同样的问题吗？