微信小程序 vant Picker组件default-index不生效的解决办法

爷傲奈我何!2024-06-02 14:29

1、原始的写法以及问题

<van-popup show="{{ showPopup && cellClick === 'Freq' }}" position="bottom" bind:close="onPopupClose">
  <van-picker value-key="Spec" show-toolbar title="{{cellClick === 'Freq' ? showPcChangeTitle : ''}}" columns="{{ cellClick === 'Freq' ? pcColumns : hcColumns }}" default-index="{{hcDefaultIndex}}" bind:cancel="onPickerCancel" bind:confirm="onPickerConfirm" bind:change="onPickerChange" />
</van-popup>

之前用 popup 结合现实 picker 显示默认值

在 onload 的时候修改默认值

const index = this.data.hcColumns.findIndex(s => s.Id === item.PrescriptionConsumableInputDtos[0].ConsumableId)
      this.setData({
        showHcName: this.data.hcColumns.filter(s => s.Id === item.PrescriptionConsumableInputDtos[0].ConsumableId)[0].Name,
        hcDefaultIndex: index
      })

结果发现虽然hcDefaultIndex的值确实改变了但是实际上页面上并没有显示为正确的选项

具体可以看 GitHub 上的一些评论单列picker，设置default-index，不起作用 · Issue #1636 · youzan/vant-weapp · GitHub

2、解决办法

在van-popup上加一个wx:if就可以了(单列和多列都是相同的修改办法)

<van-popup wx:if="{{ showPopup && cellClick === 'Freq' }}" show="{{ showPopup && cellClick === 'Freq' }}" position="bottom" bind:close="onPopupClose">
  <van-picker id="freqPicker" show-toolbar title="{{showPcChangeTitle}}" columns="{{pcColumns}}" bind:cancel="onPickerCancel" bind:confirm="onPickerConfirm" bind:change="onPickerChange" />
</van-popup>