微信小程序picker组件渲染对象数组

wxml

<picker bindChange="watchSite" mode="selector" mode:value="{{site}}" range="{{trainList}}" range-key="name">
<!--site为数组对象的序列号,range-key是对象内需要展示的属性名-->
     <view class="picker">
        当前选择：{{trainList[site].name}}
      </view>
</picker>    

　js

data:{
    trainList:[
        {
            name:'上海'
            value:0
        },
        {
            name:'南京'
            value:1
        },
        {
            name:'北京'
            value:2
        },
    ],
    site:0
},
 watchSite(e) {
    this.setData({
        site: e.detail.value
    })
    console.log('picker发送选择改变，携带值为', e.detail.value)
 },