picker组件的range-key如何显示多个字段？

<picker bindchange=“bindPickerChange” value=“{{index}}” range=“{{location}}” range-key=“{{‘name’}}”>   <view class=“picker”> 地州{{location[index]}}

 

</

view>

</picker>

location: [

  {“id”: “XM4xZnN088X5”,num:3,“name”: “西双版纳州”},

  {“id”: “yrw6F6n30igs”,num:4,“name”: “昆明市”}

]

如何写range-key让picker弹窗里显示name+num组合形式?