中被標記爲需要我在一個組件中的反應路由器中遇到鏈接問題。一旦我嘗試使用鏈接,控制檯將顯示此錯誤:失敗的上下文類型:上下文router
在Link
中被標記爲需要,但其值爲undefined
。我在這裏看到過關於這個問題的所有類似的線程,但是對於這個確切的問題沒有解決方案。我使用所有框架和組件的所有最新版本(幾天前剛剛下載了所有內容),所以它絕對不是升級任何東西。Create-React-App:路由器在鏈接
的結構是這樣的: index.js
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import registerServiceWorker from './registerServiceWorker';
import { BrowserRouter as Router, Route} from 'react-router-dom';
import { Link } from 'react-router-dom';
import About from './components/About';
import Posting from './components/Posting';
import Groups from './components/Groups';
ReactDOM.render(<App />, document.getElementById('app'));
ReactDOM.render(
<Router>
<div>
<Route exact path='/' component={About} />
<Route path='/post' component={Posting} />
<Route path='/groups' component={Groups} />
</div>
</Router>,
document.getElementById('content')
);
registerServiceWorker();
App.js
import React, { Component } from 'react';
import { BrowserRouter as Router, Route} from 'react-router-dom';
import { Link } from 'react-router-dom';
import SideMenuUserInfo from './components/sidemenu/SideMenuUserInfo';
import SideMenu from './components/sidemenu/SideMenu';
import SideMenuFooter from "./components/sidemenu/SideMenuFooter";
import TopNav from "./components/topnav/TopNav";
class App extends Component {
render() {
return(
<div className="main_container">
<div className="col-md-3 left_col">
<div className="left_col scroll-view">
<div className="navbar nav_title" style={{border: 0}}>
<a href="index.html" className="site_title"><i className="fa fa-paw"></i> <span>Logo here</span></a>
</div>
<div className="clearfix"></div>
<SideMenuUserInfo />
<br />
<SideMenu />
<SideMenuFooter />
</div>
</div>
<TopNav />
<div id="content" className="right_col" role="main">
</div>
<footer>
<div className="pull-right">
Footer text here
</div>
<div className="clearfix"></div>
</footer>
</div>
);
}
}
export default App;
SideMenuUnfoldLink.js
import React, { Component } from 'react';
import { Link } from 'react-router-dom';
class SideMenuUnfoldLink extends Component {
render() {
return(
<li>
<a>
<i className={this.props.faClass}></i>{this.props.text}<span className="fa fa-chevron-down"></span>
</a>
<ul className="nav child_menu">
<li><Link to="/">Home</Link></li> <<<<-- THE PROBLEM IS HERE
</ul>
</li>
);
};
}
export default SideMenuUnfoldLink;
而且About.js(作爲工作例子的鏈接)
import React, { Component } from 'react';
import { Link } from 'react-router-dom';
class About extends Component {
render() {
return (
<div>
<h2>Это About</h2>
<ul>
<li><Link to="/groups">Groups</Link></li>
<li><Link to="/">Main</Link></li>
</ul>
</div>
);
}
}
export default About;
該鏈接與關於組件的魅力一起使用。一旦我在SideMenuUnfoldLink組件中使用鏈接,該錯誤就會開始彈出。 我想在SideMenuUnfoldLink想要使用Link的時候路由器並沒有被初始化。但是我怎麼去解決呢?