ant-design/components/dropdown/demo/arrow.md

order	title
2	zh-CN en-US 箭头 Arrow

zh-CN

可以展示一个箭头。

en-US

You could display an arrow.

import { Menu, Dropdown, Button } from 'antd';

const menu = (
  <Menu>
    <Menu.Item>
      <a target="_blank" rel="noopener noreferrer" href="http://www.alipay.com/">
        1st menu item
      </a>
    </Menu.Item>
    <Menu.Item>
      <a target="_blank" rel="noopener noreferrer" href="http://www.taobao.com/">
        2nd menu item
      </a>
    </Menu.Item>
    <Menu.Item>
      <a target="_blank" rel="noopener noreferrer" href="http://www.tmall.com/">
        3rd menu item
      </a>
    </Menu.Item>
  </Menu>
);

ReactDOM.render(
  <>
    <Dropdown overlay={menu} placement="bottomLeft" arrow>
      <Button>bottomLeft</Button>
    </Dropdown>
    <Dropdown overlay={menu} placement="bottomCenter" arrow>
      <Button>bottomCenter</Button>
    </Dropdown>
    <Dropdown overlay={menu} placement="bottomRight" arrow>
      <Button>bottomRight</Button>
    </Dropdown>
    <br />
    <Dropdown overlay={menu} placement="topLeft" arrow>
      <Button>topLeft</Button>
    </Dropdown>
    <Dropdown overlay={menu} placement="topCenter" arrow>
      <Button>topCenter</Button>
    </Dropdown>
    <Dropdown overlay={menu} placement="topRight" arrow>
      <Button>topRight</Button>
    </Dropdown>
  </>,
  mountNode,
);

#components-dropdown-demo-arrow .ant-btn {
  margin-right: 8px;
  margin-bottom: 8px;
}
.ant-row-rtl #components-dropdown-demo-arrow .ant-btn {
  margin-right: 0;
  margin-bottom: 8px;
  margin-left: 8px;
}