错误是：A<Router> 可能只有一个子元素

Question

I have problem in React.js when I save the code the website page say:当我保存网站页面的代码时，我在 React.js 中遇到了问题：

A <Router> may have only one child element一个 <Router> 可能只有一个子元素

What is the problem and how can I solve it?有什么问题，我该如何解决？

import React, { Component } from 'react';
import Head from './component/head';
import Contacts from './component/contacts';
import { BrowserRouter as Router, Route, Switch } from 'react-router-dom'
import Addcontacts from './component/Addcontacts';

import { Provider } from "./context";

import 'bootstrap/dist/css/bootstrap.min.css';

class App extends Component {
    render() {
        return (
            <Provider>
                <Router>
                    <Head promo = 'alow' />
                    <div className='container'>
                        <Switch>
                            <Route exact path='/' Component={Contacts} />
                            <Route exact path='/add' Component={Addcontacts} />
                        </Switch>
                    </div>
                </Router>
            </Provider>
        );
    }
}

export default App;

Answer 1

you can use React.Fragment https://reactjs.org/docs/fragments.html#short-syntax to fix this issue.你可以使用 React.Fragment https://reactjs.org/docs/fragments.html#short-syntax来解决这个问题。

     <Router>
        <>
          <Head promo = 'alow' />
          <div className='container'>
            <Switch>
              <Route exact path='/' Component={Contacts} />
              <Route exact path='/add' Component={Addcontacts} />
            </Switch>
          </div>
       </>
     </Router>

So basically you just need to have a single tag in you compenent as a child.所以基本上你只需要在你小时候就拥有一个标签。

Answer 2

Inside your <Router> wrap everything in a single <div> like this在您的<Router>将所有内容都包装在一个<div>如下所示

 <Router> <div> // all your content </div> </Router>

Answer 3

Router expect this.props.children to be null or to have length equal to 1路由器期望this.props.children为空或长度等于1

In your case its more than 1在你的情况下它超过 1

So if you wrap all attr.所以如果你把所有的 attr. inside a single tag it should work fine在单个标签内它应该可以正常工作

You can use any of these您可以使用其中任何一个

<> => React.Fragment
<div> => DIV

Eg:例如：

class App extends Component {
      render() {
        return (
          <Provider>
            <Router>
                <div>
                  <Head promo = 'alow' />
                  <div className='container'>
                    <Switch>
                      <Route exact path='/' Component={Contacts} />
                      <Route exact path='/add' Component={Addcontacts} />
                    </Switch>
                  </div>
                </div>
            </Router>
          </Provider>
        );
      }
    }

错误是：A<Router> 可能只有一个子元素

问题描述

3 个解决方案

解决方案1
0 2018-10-22 15:25:30

解决方案2
0 2018-10-22 15:25:47

解决方案3
0 2018-10-22 15:35:05

错误是：A<Router> 可能只有一个子元素

问题描述

3 个解决方案

解决方案1 0 2018-10-22 15:25:30

解决方案2 0 2018-10-22 15:25:47

解决方案3 0 2018-10-22 15:35:05

解决方案1
0 2018-10-22 15:25:30

解决方案2
0 2018-10-22 15:25:47

解决方案3
0 2018-10-22 15:35:05