TypeError: Cannot read property 'getState' of null

Question

TypeError：无法读取属性 'getState' 的 null。我没有安装 redux。我正在尝试将 react antd 菜单添加到我的侧边栏页面。但问题是，如果我在我的 App.js 中添加，它不会呈现。现在我收到 TypeError: Cannot read 属性 'getState' of null。你能告诉我如何解决吗？

显示此错误：

Index.js

import React from 'react';
import ReactDOM from 'react-dom';
import 'antd/dist/antd.css';
import App from './App';

ReactDOM.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>,
  document.getElementById('root')
);

App.js

import React from 'react';
import Login from './Components/login';
import Sidebar from './Components/sidebar';
import Course from './Components/course';
import Downloads from './Components/downloads';
import Settings from './Components/settings';
import About from './Components/about';

function App() {
  return (
    <div className="container">
      <Sidebar />      
    </div>
  );
}

export default App;

代码如下：

Sidebar.js

import React from 'react';
import { Menu } from 'antd';
import { MailOutlined, CalendarOutlined } from '@ant-design/icons';

function Sidebar() {
  return (
    <React.Fragment>
      <Menu.Item key="1" icon={<MailOutlined />}>
        Courses
      </Menu.Item>
      <Menu.Item key="2" icon={<CalendarOutlined />}>
        Downloads
      </Menu.Item>
    </React.Fragment>
  );
}

export default Sidebar;

package.json

{
  "name": "udeler",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.11.4",
    "@testing-library/react": "^11.1.0",
    "@testing-library/user-event": "^12.1.10",
    "antd": "^4.9.1",
    "node-sass": "^4.14.1",
    "react": "^17.0.1",
    "react-dom": "^17.0.1",
    "react-router-dom": "^5.2.0",
    "react-scripts": "4.0.1",
    "web-vitals": "^0.2.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }
}

Answer 1

Menu.Item 组件必须出现在 Menu 组件内。

因此您需要将其包装在 Menu 组件中。

您得到的错误是因为 Menu 在内部创建了一个上下文，并且 Menu.Item 尝试访问它，但在您的情况下找不到它。

TypeError: Cannot read property 'getState' of null

TypeError: Cannot read property 'getState' of null

reactjs

react-dom