components: {
 vanPicker: Picker,
 }

 <van-picker
 show-toolbar
 :columns="columns"
 value-key="text"
 />

 //注意的点vant默认的是text，如果你需要修改需要value-key="你要定义的名字"，否则不会渲染
 this.columns = [
  {
  siteState: 1,
  text: "装机开业"
  },
  {
  siteState: 2,
  text: "装机停业"
  },
  {
  siteState: 3,
  text: "未装机开业"
  },
  {
  siteState: 4,
  text: "未装机停业"
  },
  {
  siteState: 5,
  text: "其他"
  }
 ];

data() {
 return {
 classId: -1,
 className: "全部",
 columns: [
 { text: '全部', value: -1 },
 { text: '未分组', value: 0 },
 { text: '访客', value: 1 },
 ],
 },
}

 <van-field
  readonly
  clickable
  name="picker"
  :value="className"
  label="档案组"
  placeholder=""
  @click="showClassPicker = true"
 />

 <van-popup v-model="showClassPicker" position="bottom">
 <van-picker
 show-toolbar
 :columns="columns"
 @confirm="onClassConfirm"
 @cancel="showClassPicker = false"
 />
 </van-popup>

 onClassConfirm(v) {
 this.classId = v.value;
 this.className = v.text;
 this.showClassPicker = false;
 },