无法取消SwiftUI中的模式

struct ContentView: View {
    @State private var isModalVisible = false
    
    var body: some View {
        Button("显示模态视图") {
            isModalVisible = true
        }
        .sheet(isPresented: $isModalVisible) {
            ModalView(isVisible: $isModalVisible)
        }
    }
}

struct ModalView: View {
    @Binding var isVisible: Bool
    
    var body: some View {
        VStack {
            Text("这是一个模态视图")
            Button("取消") {
                isVisible = false
            }
        }
    }
}