[英]How to pass a variable from one page to another in ReactJS?
我已經導出了多個變量,但是出於某種原因,我用於存儲該變量的方法似乎不起作用。 我有登錄頁面,該頁面將正確的值存儲到“ ID”中,如下所示
import AuthService from './AuthService';
let ID = "";
class LoginPage extends Component {
constructor(props) {
super(props);
this.state = {
username: '',
password: ''
}
this.handleChange = this.handleChange.bind(this);
this.handleFormSubmit = this.handleFormSubmit.bind(this);
this.Auth = new AuthService();
}
handleFormSubmit(e){
e.preventDefault();
this.Auth.login(this.state.username,this.state.password)
.then(res =>{
if(this.Auth.state.isA)
this.props.history.push('/AdminApp');
else if(this.Auth.state.isA === 0 && this.Auth.state.sub === 0)
{
ID = this.Auth.state.userID;
console.log(ID) // This prints the right value
this.props.history.push('/SDForm')
}
})
.catch(err =>{
alert(err);
})
}
handleChange = event => {
this.setState({
[event.target.id]: event.target.value
});
}
render() {
return (
<Container>
<Col className="UCFLogo"><img src={logo} /></Col>
<Form className="LoginForm">
<Col>
<h1 className="mainTitles">Senior Design Project Selection</h1>
<h3 className="subTitle">Sign In</h3>
</Col>
<Col>
<FormGroup className="LoginPad">
<Label className="subTitle">Knights Email</Label>
<Input className="LoginInfo" type="text" name="username" id="username" onChange={this.handleChange.bind(this)} value={this.state.username} />
</FormGroup>
</Col>
<Col>
<FormGroup>
<Label className="subTitle" for="password">Password</Label>
<Input className="LoginInfo" type="password" name="password" id="password" onChange={this.handleChange.bind(this)} value={this.state.password} />
</FormGroup>
</Col>
<Button className="subTitle" onClick={this.handleFormSubmit}>Submit</Button>
</Form>
</Container>
);
}
}
export default LoginPage;
export {ID};
然后,我需要將登錄時的ID加載到form.js文件中的狀態(如下所示)中,以便在提交時將其返回到json,我只是嘗試將ID打印到控制台,直到我知道得到正確的值,並且出於長度的考慮,我剪切掉了大部分代碼,但是我在控制台中得到了
ƒ LoginPage(props) {
var _this;
Object(C_csform_master_node_modules_babel_runtime_helpers_esm_classCallCheck__WEBPACK_IMPORTED_MODULE_1__["default"])(this, LoginPage);
_this = Object(C_cs…
form.js
import ID from './LoginPage';
const Auth = new AuthService();
class SDForm extends Component {
constructor(props) {
super(props);
this.state = {
firstName: "",
lastName: "",
ID: "",
}
this.Auth = new AuthService();
this.handleFormSubmit = this.handleFormSubmit.bind(this);
}
printToConsole = () => {
console.log(ID)
}
render() {
return (
<Container>
<Form className="SDForm">
// Form stuff
<Col className="subTitle">
<Button onClick={this.printToConsole}>Submit</Button>
</Col>
</Form>
</Container>
);
}
}
export default withAuth(SDForm);
這不是在React中組件之間傳遞信息的正確方法。 在大多數情況下,最好的方法是將ID
的值放在Redux存儲中,或將ID
值存儲到它們的狀態中,然后將ID
狀態作為道具傳遞給SDForm
組件,如下所示:
import SDForm from './SDForm.js'
和它們(一旦獲得ID
值並將其存儲在state
):
const { ID } = this.state;
然后在<SDForm />
中使用您認為合適的ID
prop。
<SDForm id={ID} />
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