edu-mini/components/picker/picker.wxml

<picker bindchange="bindChange" value="{{position}}" range="{{pickData}}" range-key="{{key}}">
    <van-field required="{{ required }}" value="{{pickData[position][key]}}" label="{{label}}" readonly is-link center
               input-align="right" placeholder="{{placeholder||'请选择'+label}}"/>
</picker>