在通过钩子制作登录/注册组件时,我用钩子为登录、注销、注册和用户制作了单独的功能。
因为钩子对我来说更容易,所以在执行 npm start 后,没有显示错误。
应用程序.js:
import React,{useState} from 'react';
import Users from './Users'
const App=()=> {
const [user,setUser]=useState('')
return (
<div style={{padding:8}} className="container">
<Users user={user} setUser={setUser}/>
<br/>
<hr/>
</div>
);
}
export default App
登录.js:
import React,{useState} from 'react'
const Login=(setUser)=>{
const [username,setUsername]=useState('');
const handleUserName=(event)=>{
setUsername(event.target.value)
}
return(
<form onSubmit={e => { e.preventDefault(); setUsername(username) }}>
<label htmlFor="login-username">Username:</label>
<input type="text" value={username} onChange={handleUserName} name="login-username" id="login-username" />
<label htmlFor="login-password">Password:</label>
<input type="password" name="login-password" id="login-password" />
<input type="submit" value="Login" disabled={username.length === 0} />
</form>
)
}
export default Login
注销.js:
import React from 'react'
const Logout=(user,setUser)=>{
return(
<form onSubmit={e=>{e.preventDefault();setUser('')}}>
Logged in As:<b>{user}</b>
<input type="submit" value="Logout"></input>
</form>
)
}
export default Logout
注册.js:
import React,{useState} from 'react'
const Register=(setUser)=>{
const [username,setUsername]=useState('')
const [password,setPassword]=useState('')
const [passwordRepeat,setPasswordRepeat]=useState('')
const handleUserName=(event)=>{
setUsername(event.target.value)
}
const handlePassword=(event)=>{
setPassword(event.target.value)
}
const handlePasswordRepeat=(event)=>{
setPasswordRepeat(event.target.value)
}
return(
<form onSubmit={e=>{e.preventDefault();setUsername(username)}}>
<label htmlFor="register-username">Username:</label>
<input type="text" value={username} onChange={handleUserName} name="register-username" id="register-username"/>
<br/>
<label htmlFor="register-password">Password:</label>
<input type="password" value={password} onChange={handlePassword} name="register-password" id="register-password"/>
<br/>
<label htmlFor="register-password-repeat">repeat password:</label>
<input type="password" value={passwordRepeat} onChange={handlePasswordRepeat} name="register-password-repeat" id="register-password-repeat"/>
<input type="submit" value="Register" disabled={username.length===0||password.length===0||password!==passwordRepeat}/>
</form>
)
}
export default Register
用户.js:
import React,{useState} from 'react'
import Login from './Login'
import Logout from './Logout'
import Register from './Register'
const User=()=>{
const {user,setUser}=useState('');
if (user){
return <Logout user={user} setUser={setUser}/>
} else {
return (
<React.Fragment>
<Login setUser={setUser}/>
<br/>
<Register setUser={setUser}/>
</React.Fragment>
)
}
}
export default User;
没有显示错误,但是当我尝试注册用户名时,它显示TypeError: setUser is not a function reacjs in register.js 行<form onSubmit={e=>{e.preventDefault();setUser(username)}}>
我对 reactJS 很陌生,我知道我在调用 setUser 时做错了......但它似乎是 react 自己的功能。
如果你给我任何解释的解决方案,这将是一个很好的学习方式。我想修改代码并以我自己可以理解的方式编写这些代码。
提前谢谢