ant-design-vue/components/cascader/demo/custom-trigger.md

#### 可以自定义显示 切换按钮和结果分开。 #### Custom trigger Separate trigger button and result.

<template>
  <span>
    {{text}}
    &nbsp;
    <a-cascader :options="options" @change="onChange">
      <a href="#">Change city</a>
    </a-cascader>
  </span>
</template>
<script>
export default {
  data() {
    return {
      text: 'Unselect',
      options: [{
        value: 'zhejiang',
        label: 'Zhejiang',
        children: [{
          value: 'hangzhou',
          label: 'Hangzhou',
          children: [{
            value: 'xihu',
            label: 'West Lake',
          }],
        }],
      }, {
        value: 'jiangsu',
        label: 'Jiangsu',
        children: [{
          value: 'nanjing',
          label: 'Nanjing',
          children: [{
            value: 'zhonghuamen',
            label: 'Zhong Hua Men',
          }],
        }],
      }]
    }
  },
  methods: {

    onChange(value, selectedOptions) {
      this.text = selectedOptions.map(o => o.label).join(', ');
    }
  }
}
</script>