<cn>
#### 动态加载选项
使用 `loadData` 实现动态加载选项。
> 注意：`loadData` 与 `showSearch` 无法一起使用。
</cn>

<us>
#### Load Options Lazily
Load options lazily with `loadData`.
> Note: `loadData` cannot work with `showSearch`.
</us>

```html
<template>
  <a-cascader :options="options" @change="onChange" :loadData="loadData" placeholder="Please select" changeOnSelect/>
</template>
<script>
export default {
  data() {
    return {
      options: [{
        value: 'zhejiang',
        label: 'Zhejiang',
        isLeaf: false,
      }, {
        value: 'jiangsu',
        label: 'Jiangsu',
        isLeaf: false,
      }]
    }
  },
  methods: {
    onChange(value) {
      console.log(value);
    },
    loadData(selectedOptions) {
      const targetOption = selectedOptions[selectedOptions.length - 1];
      targetOption.loading = true;

      // load options lazily
      setTimeout(() => {
        targetOption.loading = false;
        targetOption.children = [{
          label: `${targetOption.label} Dynamic 1`,
          value: 'dynamic1',
        }, {
          label: `${targetOption.label} Dynamic 2`,
          value: 'dynamic2',
        }];
        this.options = [...this.options]
      }, 1000);
    }
  }
}
</script>
```