---
order: 99
debug: true
title:
  zh-CN: 嵌套
  en-US: Nest
---

## zh-CN

默认选中第一项。

## en-US

Default activate first tab.

```tsx
import { Select, Tabs } from 'antd';
import React, { useState } from 'react';

const { Option } = Select;

const positionList = ['left', 'right', 'top', 'bottom'];

const App: React.FC = () => {
  const [parentPos, setParentPos] = useState(undefined);
  const [childPos, setChildPos] = useState(undefined);
  const [parentType, setParentType] = useState(undefined);
  const [childType, setChildType] = useState(undefined);

  return (
    <div>
      <Select
        style={{ width: 200 }}
        onChange={val => {
          setParentPos(val);
        }}
      >
        {positionList.map(pos => (
          <Option key={pos} value={pos}>
            Parent - {pos}
          </Option>
        ))}
      </Select>

      <Select
        style={{ width: 200 }}
        onChange={val => {
          setChildPos(val);
        }}
      >
        {positionList.map(pos => (
          <Option key={pos} value={pos}>
            Child - {pos}
          </Option>
        ))}
      </Select>

      <Select
        style={{ width: 200 }}
        onChange={val => {
          setParentType(val);
        }}
      >
        <Option value="line">Parent - line</Option>
        <Option value="card">Parent - card</Option>
        <Option value="editable-card">Parent - card edit</Option>
      </Select>

      <Select
        style={{ width: 200 }}
        onChange={val => {
          setChildType(val);
        }}
      >
        <Option value="line">Child - line</Option>
        <Option value="card">Child - card</Option>
        <Option value="editable-card">Parent - card edit</Option>
      </Select>

      <Tabs
        defaultActiveKey="1"
        tabPosition={parentPos}
        type={parentType}
        items={[
          {
            label: 'Tab 1',
            key: '1',
            children: (
              <Tabs
                defaultActiveKey="1"
                tabPosition={childPos}
                type={childType}
                style={{ height: 300 }}
                items={new Array(20).fill(null).map((_, index) => {
                  const key = String(index);

                  return {
                    label: `Tab ${key}`,
                    key,
                    children: `TTTT ${key}`,
                  };
                })}
              />
            ),
          },
          {
            label: 'Tab 2',
            key: '2',
            children: 'Content of Tab Pane 2',
          },
        ]}
      />
    </div>
  );
};

export default App;
```