```html
<ui-tree
  v-model="selectedValue"
  :data="treeData"
  :data-format="dataFormat"
  :max-level="3"
  autoExpandSelected
>
  <p>selectedValue: {{ selectedValue }}</p>
</ui-tree>
```

```js
export default {
  data() {
    return {
      dataFormat: { label: 'title', value: 'key' },
      treeData: [
        {
          title: 'node1',
          key: '1',
          children: [
            {
              title: 'node1-1',
              key: '1-1',
              children: [
                {
                  title: 'node1-1-1',
                  key: '1-1-1',
                  children: [
                    {
                      title: 'node1-1-1-1',
                      key: '1-1-1-1'
                    }
                  ]
                }
              ]
            },
            {
              title: 'node1-2',
              key: '1-2',
              children: [
                {
                  title: 'node1-2-1',
                  key: '1-2-1'
                }
              ]
            }
          ]
        }
      ],
      selectedValue: '1-1-1',
    };
  }
};
```
