如何实现一个下拉菜单？

@State sex:string = "选择性别"
@Builder SexMenu(){
  Menu(){
    MenuItem({content:"男"})
      .onChange((selected:boolean)=>{
        this.sex = "男"
      })
    MenuItem({content:"女"})
      .onChange((selected:boolean)=>{
        this.sex = "女"
      })
  }
}
build() {
  Column() {
    Text(this.sex)
      .borderWidth(1)
      .padding(10)
      .bindMenu(this.SexMenu())
  }.width("100%")
  .height("100%")
  .justifyContent(FlexAlign.Center)
}