[英]React Hook "useTranslation" cannot be called in a class component
[英]React Hook “useContext” cannot be called in a class component
得到以下錯誤。 請幫助解決這個問題。 第 9:36 行:無法在 class 組件中調用 React Hook “useContext”。 必須在 React function 組件或自定義 React Hook function react-hooks/rules-of-hooks Line 9:47: 'AccountContext' is not defined no-undef Line 126:37 中調用 React Hooks:無非定義
搜索關鍵字以了解有關每個錯誤的更多信息。
import React, { useContext } from "react";
import { BoldLink, BoxContainer, FormContainer, MutedLink, SubmitButton, Input } from "./common";
import { Marginer } from "../marginer";
export class LoginForm extends React.Component {
constructor() {
const { switchToSignup } = useContext(AccountContext);
super();
this.state = {
input: {},
errors: {}
};
this.handleChange = this.handleChange.bind(this);
this.handleSubmit = this.handleSubmit.bind(this);
}
handleChange(event) {
let input = this.state.input;
input[event.target.name] = event.target.value;
this.setState({
input
});
}
handleSubmit(event) {
event.preventDefault();
if(this.validate()){
console.log(this.state);
let input = {};
input["email"] = "";
input["password"] = "";
this.setState({input:input});
alert('Demo Form is submitted');
}
}
validate(){
let input = this.state.input;
let errors = {};
let isValid = true;
if (!input["email"]) {
isValid = false;
errors["email"] = "Please enter your email Address.";
}
if (typeof input["email"] !== "undefined") {
var pattern = new RegExp(/^(("[\w-\s]+")|([\w-]+(?:\.[\w-]+)*)|("[\w-\s]+")([\w-]+(?:\.[\w-]+)*))(@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$)|(@\[?((25[0-5]\.|2[0-4][0-9]\.|1[0-9]{2}\.|[0-9]{1,2}\.))((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\.){2}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\]?$)/i);
if (!pattern.test(input["email"])) {
isValid = false;
errors["email"] = "Please enter valid email address.";
}
}
if (!input["password"]) {
isValid = false;
errors["password"] = "Please enter your password.";
}
if (typeof input["password"] !== "undefined") {
if(input["password"].length < 6){
isValid = false;
errors["password"] = "Please add at least 6 charachter.";
}
}
this.setState({
errors: errors
});
return isValid;
}
render() {
return (
<div>
<form onSubmit={this.handleSubmit}>
<BoxContainer>
<FormContainer>
<div class="form-group">
<Input
type="text"
name="email"
value={this.state.input.email}
onChange={this.handleChange}
class="form-control"
placeholder="Enter email"
id="email" />
<div className="text-danger">{this.state.errors.email}</div>
</div>
<div class="form-group">
<Input
type="password"
name="password"
value={this.state.input.password}
onChange={this.handleChange}
class="form-control"
placeholder="Enter password"
id="password" />
<div className="text-danger">{this.state.errors.password}</div>
</div>
</FormContainer>
<Marginer direction="vertical" margin={10} />
<MutedLink href="#">Forget your password?</MutedLink>
<Marginer direction="vertical" margin="1.6em" />
<SubmitButton type="submit">Signin</SubmitButton>
<Marginer direction="vertical" margin="1em" />
<MutedLink href="#">
Don't have an accoun?{" "}
<BoldLink href="#" onClick={switchToSignup}>
Signup
</BoldLink>
</MutedLink>
</BoxContainer>
</form>
</div>
);
}
}
如錯誤消息所述,您不能混合使用掛鈎和 class 組件。 您要么需要將LoginForm
切換為 function 組件,要么直接使用AccountContext.Consumer
,例如:
render() {
return (
<AccountContext.Consumer>
(({ switchToSignup }) => (
<div>
// do something with switchToSignup
</div>
))
</AccountContext.Consumer>
);
}
看起來您也忘記了導入AccountContext
。 您還需要確保AccountContext.Provider
安裝在應用程序樹中此組件上方的某個位置。 要閱讀有關 React Context 的更多信息,請查看文檔。
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