Question

我是React和JS的新手，正在尝试为我的CRUD SpringBoot应用程序实现React前端。我正在尝试将ButtonDropdown添加到我的页面之一。

代码如下：

通用 buttondrop.js

import React, { Component, useState } from 'react';
import { ButtonDropdown, DropdownMenu, DropdownItem, DropdownToggle } from 'reactstrap';
import Dropdown from 'react-bootstrap/Dropdown';
import DropdownButton from 'react-bootstrap/DropdownButton';

const Bdrop = (props) => {
  const [dropdownOpen, setOpen] = useState(false);

  const toggle = () => setOpen(!dropdownOpen);

  return (
    <ButtonDropdown isOpen={dropdownOpen} toggle={toggle}>
      <DropdownToggle caret>
        Button Dropdown
      </DropdownToggle>
      <DropdownMenu>
            <Dropdown.Item href="#/action-1">Action</Dropdown.Item>
            <Dropdown.Item href="#/action-2">Another action</Dropdown.Item>
            <Dropdown.Item href="#/action-3">Something else</Dropdown.Item>
      </DropdownMenu>
    </ButtonDropdown>
  );
}

App.js

import React, { Component } from 'react';
import './App.css';
import Home from './Home';
import { BrowserRouter as Router, Route, Switch } from 'react-router-dom';
import CustomerList from './CustomerList';
import EmployeeList from './EmployeeList';
import CustomerEdit from './CustomerEdit';
import EmployeeEdit from './EmployeeEdit';
import SessionList from './SessionList';
import Bdrop from './buttondrop';


class App extends Component {
  render() {
    return (
      <Router>
        <Switch>
          <Route path='/' exact={true} component={Home}/>
          <Route path='/customers' exact={true} component={CustomerList}/>
          <Route path='/customer/:id' component={CustomerEdit}/>
          <Route path='/employees' exact={true} component={EmployeeList}/>
          <Route path='/employee/:id' component={EmployeeEdit}/>
          <Route path='/sessions' exact={true} component={SessionList}/>
          <Route path='/buttondrop' component={() => <Bdrop /> }/>


        </Switch>
      </Router>
    )
  }
}

index.js

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import * as serviceWorker from './serviceWorker';
import 'bootstrap/dist/css/bootstrap.min.css';

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


serviceWorker.unregister();

CustomerList.js

import React, { Component, useState } from 'react';
import { Button, ButtonGroup, Container, Table} from 'reactstrap';
import { ButtonDropdown, DropdownMenu, DropdownItem, DropdownToggle } from 'reactstrap';
import Dropdown from 'react-bootstrap/Dropdown';
import DropdownButton from 'react-bootstrap/DropdownButton'
import AppNavbar from './AppNavbar';
import { Link } from 'react-router-dom';
import Bdrop from './buttondrop';


class CustomerList extends Component {

    constructor(props) {
        super(props);
        this.state = {
          customers: [],
          isLoading: true

        };
        this.remove = this.remove.bind(this);
    }

    componentDidMount() {
        this.setState({isLoading: true});

        fetch('/api/customers')
            .then(response => response.json())
            .then(data => this.setState({customers: data, isLoading: false}))

    }

    async remove(id) {
        await fetch(`/api/customer/${id}`, {
          method: 'DELETE',
          headers: {
            'Accept': 'application/json',
            'Content-type': 'application/json'
          }
        }).then(() => {
          let updatedCustomers = [...this.state.customers].filter(i => i.customer_id !== id);
          this.setState({customers: updatedCustomers});
        });
    }

    render() {

      const {customers, isLoading} = this.state;


      if(isLoading) {
        return<p> Loading...</p>;
      }


      const customerList = customers.map(customer => {
      return <tr key={customer.customer_id}>
        <td style={{whiteSpace: 'nowrap'}}>{customer.customer_id}</td>
        <td>{customer.first_name}</td>
        <td>{customer.last_name}</td>
        <td>{customer.phone_number}</td>

        <td>
          <ButtonGroup>
            <Button size="sm" color="primary" tag={Link} to={"/customer/" + customer.customer_id}>Edit</Button>
            <Button size="sm" color="danger" onClick={() => this.remove(customer.customer_id)}>Delete</Button>
          </ButtonGroup>
        </td>
      </tr>
    });



    return (
      <div>
        <AppNavbar/>
        <Container fluid>
          <div className="float-right">
            <Button color="success" tag={Link} to="customer/new">Add Customer</Button>
          </div>
          <h3>Customers</h3>
      {   /* <Bdrop/> */ }

          <Table className="mt-4">
            <thead>
            <tr>
              <th width="15%">Customer ID</th>
              <th width="20%">First Name</th>
              <th width="20%">Last Name</th>
              <th width="20%">Phone Number</th>
              <th width="10%">Actions</th>
            </tr>
            </thead>
            <tbody>
            {customerList}
            </tbody>
          </Table>
        </Container>
      </div>
    );


}
}
export default CustomerList;

Home.js

import React, { Component } from 'react';
import './App.css';
import AppNavbar from './AppNavbar';
import { Link } from 'react-router-dom';
import { Button, Container } from 'reactstrap';
import { ButtonDropdown, DropdownMenu, DropdownItem, DropdownToggle } from 'reactstrap';
import Dropdown from 'react-bootstrap/Dropdown';
import DropdownButton from 'react-bootstrap/DropdownButton'

class Home extends Component {
  render() {
    return (
      <div>
        <AppNavbar/>
        <Container fluid>
           <h3>Welcome to GMusicAcademy Manager</h3>

        </Container>
        <Container fluid>
          <Button color="link"><Link to="/customers">Manage GMusicAcademy Customers</Link></Button>
          <Button color="link"><Link to="/employees">Manage GMusicAcademy Employees</Link></Button>
          <Button color="link"><Link to="/sessions">Manage GMusicAcademy Sessions</Link></Button>
          <Button color="link"><Link to="/buttondrop">Manage GMusicAcademy ButtonDropDown</Link></Button>

        </Container>
      </div>
    );
  }
}

export default Home;

目标是在此处将Bdrop添加到CustomerList（在代码中已注释掉）：

<h3>Customers</h3>
     <Bdrop/> 
     <Table className="mt-4">

这将导致“无效的挂钩调用错误”。我有相同版本的react和react-dom，所以不是那样。

为了尝试帮助解决此问题，我决定尝试创建一条通往Bdrop的路线，只是看我是否能够使其完全正常工作，但这也不起作用。我尝试过类似的事情：

<Route path='/buttondrop' component={() => <Bdrop /> }/>

或

<Route path='/buttondrop' render={() => <Bdrop /> }/>

这也会导致“无效的钩子错误”。

我尝试过

<Route path='/buttondrop'> <Bdrop /> </Route>

这会导致“ React.Children.only预期会收到一个React元素的孩子”错误。

请帮助！理想情况下，我希望了解这两个问题。

Answer 1

这里是sandbox link到具有有效<Bdrop />组件的版本。

在不知道您正在使用的Bootstrap，react-bootstrap和reactstrap的版本的情况下，很难说这是否是造成您麻烦的原因。

React-bootstrap-无效的挂钩调用-ButtonDropdown

1 个答案: