我尝试在应用中使用useContext挂钩而不是Redux。标头组件和登录页面使用相同的上下文。两者都是使用上下文提供程序的路由组件的子级。在注册表单中,我使用硬编码数据检查功能。注册后标头不会重新呈现。
App.js(登录组件)
import React, { useContext, useState } from "react";
import { ExamContext } from "./Context/ExamContext";
function App() {
const [user, setUser] = useState("");
const [pass, setPass] = useState("");
const { role, login } = useContext(ExamContext);
const handleSubmit = () => {
login(user, "Admin");
};
return (
<React.Fragment>
<div className="appbg">
<div className="container">
<div className="panel panel-success" style={{ marginTop: 20 }}>
<div className="panel-heading">Login Forms</div>
<div className="panel-body">
<div className="form-group">
<label>Email</label>
<input
type="text"
className="form-control"
value={user}
onChange={e => setUser(e.target.value)}
/>
</div>
</div>
<div className="panel-body">
<div className="form-group">
<label>Password</label>
<input
type="password"
className="form-control"
value={pass}
onChange={e => setPass(e.target.value)}
/>
</div>
</div>
<button className="btn btn-success" onClick={handleSubmit}>
Submit
</button>
</div>
</div>
</div>
</React.Fragment>
);
}
export default App;
标题组件
const Header = () => {
const { role } = useContext(ExamContext);
const [user] = useState(role);
switch (user) {
case "Admin":
return (
<div>
<h4>Admin</h4>
</div>
);
case "User":
return (
<div>
<h4>User</h4>
</div>
);
default:
return (
<div>
<h4>No User</h4>
</div>
);
}
};
export default Header;
和背景
import React, { createContext, useState } from "react";
const ExamContext = createContext();
const ExamConProvider = ({ children }) => {
const [user, setUser] = useState("");
const [role, setRole] = useState("NoUser");
const login = (getuser, getrole) => {
setRole(getrole);
setUser(getuser);
};
return (
<ExamContext.Provider value={{ user, role, login }}>
{children}
</ExamContext.Provider>
);
};
export { ExamContext, ExamConProvider };
索引. js
import React from 'react';
import ReactDOM from 'react-dom';
import Routing from './components/Routing';
import { ExamConProvider } from './Context/ExamContext'
import './scss/style.scss';
ReactDOM.render(
<ExamConProvider>
<Routing />
</ExamConProvider>
,document.getElementById("root"))
路由模块
import React from 'react';
import { BrowserRouter, Route } from 'react-router-dom';
import App from '../App';
import Home from '../containers/Home';
import Header from '../components/Header';
import Footer from '../components/Footer';
const Routing = () => {
return(
<BrowserRouter>
<Header />
<Route exact path="/" component={App}></Route>
<Route path="/home" component={Home}></Route>
<Footer />
</BrowserRouter>
)
}
export default Routing;
2条答案
按热度按时间6jygbczu1#
不确定您是否在询问为什么标头不重新呈现。如果是,原因是您没有将
Context Provider
添加到<App />
中。您应该像下面这样添加它:
干杯!
ktecyv1j2#
您应该尝试在登录组件上使用setUser和setRole状态,而不是使用上下文函数。
在登录组件中,尝试以下操作: