Javascript 更换道具后,componentDidMount不断重复调用
当我这样做时,无限循环组件didmount会无限调用自身,这是一个问题:Javascript 更换道具后,componentDidMount不断重复调用,javascript,reactjs,react-router,ecmascript-5,Javascript,Reactjs,React Router,Ecmascript 5,当我这样做时,无限循环组件didmount会无限调用自身,这是一个问题: this.props.setRootState({industries: ['hello','world']}); import React from 'react'; import {Route, Link} from 'react-router-dom'; import FourthView from '../fourthview/fourthview.component'; import {Bootstrap, G
this.props.setRootState({industries: ['hello','world']});
import React from 'react';
import {Route, Link} from 'react-router-dom';
import FourthView from '../fourthview/fourthview.component';
import {Bootstrap, Grid, Row, Col, Button, Image, Modal, Popover} from 'react-bootstrap';
import Header from '../header/header.component';
import style from './information.style.scss';
import industryApi from '../industries/industry.api';
class InformationFilter extends React.Component {
constructor(props) {
super(props);
this.state = {};
}
componentDidMount() {
industryApi.getAll().then(response => {
if (response.data) {
this.props.setRootState({industries: response.data._embedded.industries});
} else {
console.log(response);
}
});
}
onIndustryChangeOption(event) {
this.props.setRootState({selectedIndustry: event.target.value});
}
onJobChangeOption(event) {
this.props.setRootState({selectedJob: event.target.value});
}
render() {
return (
<div className={"wrapperDiv"}>
<div className={"flexDivCol"}>
<div id="header">
<Header size="small"/>
</div>
<div id="industryFilter">
<h2 className={"center"} style={{marginBottom: '25px'}}>Tietoa Aloista</h2>
<p className={"primaryColor center"}>Valitse opintoala</p>
<div className={"industries dropdownListHolder center"}>
<select id={"dropdownList"} onChange={(e) => this.onIndustryChangeOption(e)}
value={this.props.rootState.selectedIndustry}>
{this.props.rootState.industries.map((industry, i) => <option key={i}
value={industry.id}>{industry.title}</option>)}
</select>
</div>
<p className={"primaryColor center"}>Valitse työtehtävä</p>
<div className={"jobs dropdownListHolder center"}>
<select id={"dropdownList"} onChange={(e) => this.onJobChangeOption(e)}
value={this.props.rootState.selectedJob}>
{this.props.rootState.industries.map((job, i) => <option key={i}
value={job.id}>{job.text}</option>)}
</select>
</div>
</div>
<div id="industryDescription">
<h4>Ravintola- ja cateringala</h4>
<p className={"secondaryColor"}>
Donec facilisis tortor ut augue lacinia, at viverra est semper.
Sed sapien metus, scelerisque nec pharetra id, tempor a tortor. Pellentesque non dignissim
neque. Ut porta viverra est, ut dignissim elit elementum ut. Nunc vel rhoncus nibh, ut
tincidunt turpis. Integer ac enim pellentesque, adipiscing metus id, pharetra odio.
</p>
<p className={"secondaryColor"}>
Donec facilisis tortor ut augue lacinia, at viverra est semper.
Sed sapien metus, scelerisque nec pharetra id, tempor a tortor. Pellentesque non dignissim
neque. Ut porta viverra est, ut dignissim elit elementum ut. Nunc vel rhoncus nibh, ut
tincidunt turpis. Integer ac enim pellentesque, adipiscing metus id, pharetra odio.
</p>
</div>
<div id={"btnFilter"}>
<Link to='/information-job'>
<div onClick={() => this.props.setRootState({globalVariable: 'bar'})}>
<Button className={"primaryBtn"}>Seuraava</Button>
</div>
</Link>
</div>
</div>
</div>
);
}
}
export default InformationFilter;
整个代码如下所示:
this.props.setRootState({industries: ['hello','world']});
import React from 'react';
import {Route, Link} from 'react-router-dom';
import FourthView from '../fourthview/fourthview.component';
import {Bootstrap, Grid, Row, Col, Button, Image, Modal, Popover} from 'react-bootstrap';
import Header from '../header/header.component';
import style from './information.style.scss';
import industryApi from '../industries/industry.api';
class InformationFilter extends React.Component {
constructor(props) {
super(props);
this.state = {};
}
componentDidMount() {
industryApi.getAll().then(response => {
if (response.data) {
this.props.setRootState({industries: response.data._embedded.industries});
} else {
console.log(response);
}
});
}
onIndustryChangeOption(event) {
this.props.setRootState({selectedIndustry: event.target.value});
}
onJobChangeOption(event) {
this.props.setRootState({selectedJob: event.target.value});
}
render() {
return (
<div className={"wrapperDiv"}>
<div className={"flexDivCol"}>
<div id="header">
<Header size="small"/>
</div>
<div id="industryFilter">
<h2 className={"center"} style={{marginBottom: '25px'}}>Tietoa Aloista</h2>
<p className={"primaryColor center"}>Valitse opintoala</p>
<div className={"industries dropdownListHolder center"}>
<select id={"dropdownList"} onChange={(e) => this.onIndustryChangeOption(e)}
value={this.props.rootState.selectedIndustry}>
{this.props.rootState.industries.map((industry, i) => <option key={i}
value={industry.id}>{industry.title}</option>)}
</select>
</div>
<p className={"primaryColor center"}>Valitse työtehtävä</p>
<div className={"jobs dropdownListHolder center"}>
<select id={"dropdownList"} onChange={(e) => this.onJobChangeOption(e)}
value={this.props.rootState.selectedJob}>
{this.props.rootState.industries.map((job, i) => <option key={i}
value={job.id}>{job.text}</option>)}
</select>
</div>
</div>
<div id="industryDescription">
<h4>Ravintola- ja cateringala</h4>
<p className={"secondaryColor"}>
Donec facilisis tortor ut augue lacinia, at viverra est semper.
Sed sapien metus, scelerisque nec pharetra id, tempor a tortor. Pellentesque non dignissim
neque. Ut porta viverra est, ut dignissim elit elementum ut. Nunc vel rhoncus nibh, ut
tincidunt turpis. Integer ac enim pellentesque, adipiscing metus id, pharetra odio.
</p>
<p className={"secondaryColor"}>
Donec facilisis tortor ut augue lacinia, at viverra est semper.
Sed sapien metus, scelerisque nec pharetra id, tempor a tortor. Pellentesque non dignissim
neque. Ut porta viverra est, ut dignissim elit elementum ut. Nunc vel rhoncus nibh, ut
tincidunt turpis. Integer ac enim pellentesque, adipiscing metus id, pharetra odio.
</p>
</div>
<div id={"btnFilter"}>
<Link to='/information-job'>
<div onClick={() => this.props.setRootState({globalVariable: 'bar'})}>
<Button className={"primaryBtn"}>Seuraava</Button>
</div>
</Link>
</div>
</div>
</div>
);
}
}
export default InformationFilter;
从“React”导入React;
从'react router dom'导入{Route,Link};
从“../FourthView/FourthView.component”导入第四视图;
从“react Bootstrap”导入{Bootstrap、Grid、Row、Col、Button、Image、Modal、Popover};
从“../Header/Header.component”导入标题;
从“/information.style.scss”导入样式;
从“../industries/industry.api”导入industryApi;
类InformationFilter扩展了React.Component{
建造师(道具){
超级(道具);
this.state={};
}
componentDidMount(){
industryApi.getAll().then(响应=>{
if(response.data){
this.props.setRootState({industries:response.data._embedded.industries});
}否则{
控制台日志(响应);
}
});
}
onIndustryChangeOption(事件){
this.props.setRootState({selectedIndustry:event.target.value});
}
onJobChangeOption(事件){
this.props.setRootState({selectedJob:event.target.value});
}
render(){
返回(
阿洛伊斯塔酒店
Valitse opintoala
此.onIndustryChangeOption(e)}
value={this.props.rootState.selectedIndustry}>
{this.props.rootState.industries.map((行业,i)=>{industry.title}}
Valitse työtehtävä
此.onJobChangeOption(e)}
value={this.props.rootState.selectedJob}>
{this.props.rootState.industries.map((作业,i)=>{job.text}
拉文托拉-卡特林加拉酒店
viverra est semper的Donec facilisis tortor ut augue lacinia。
塞德·萨皮安·梅特斯,权杖,临时侵权人。佩伦特式的无尊严
内克。我们的生命之门,我们的尊严,我们的精英元素,我们的力量,我们的力量
turpis是一个整数,它的名字叫pellentesque,名字叫metus,名字叫pharetra odio。
viverra est semper的Donec facilisis tortor ut augue lacinia。
塞德·萨皮安·梅特斯,权杖,临时侵权人。佩伦特式的无尊严
内克。我们的生命之门,我们的尊严,我们的精英元素,我们的力量,我们的力量
turpis是一个整数,它的名字叫pellentesque,名字叫metus,名字叫pharetra odio。
this.props.setRootState({globalVariable:'bar'})}>
瑟拉瓦
);
}
}
导出默认信息过滤器;
Routes.js
import React from "react";
import {HashRouter, Route, Switch, Redirect, Link} from 'react-router-dom';
import Main from './components/main/main.component';
import SecondView from './components/secondview/secondview.component';
import ThirdView from './components/thirdview/thirdview.component';
import Traineeship from './components/traineeship/traineeships.component';
import InformationFilter from "./components/information/information-filter.component";
import InformationJob from "./components/information/information-job.component";
class AppRoutes extends React.Component {
constructor(props) {
super(props);
this.state = {
selectedIndustry: '',
selectedJob: '',
industries: [],
jobs: [],
}
}
render() {
const InformationFilterPage = () => <InformationFilter rootState={this.state}
setRootState={this.setState.bind(this)}/>;
const InformationJobPage = () => <InformationJob rootState={this.state}
setRootState={this.setState.bind(this)}/>;
const TraineeshipPage = () => <Traineeship rootState={this.state}
setRootState={this.setState.bind(this)}/>;
return (
<HashRouter>
<Switch>
<Route exact path='/' component={Main}/>
<Route path='/secondview' component={SecondView}/>
<Route path='/traineeships' component={TraineeshipPage}/>
<Route path='/information-filter' component={InformationFilterPage}/>
<Route path='/information-job' component={InformationJobPage}/>
<Redirect from='*' to='/'/>
</Switch>
</HashRouter>
);
}
}
export default AppRoutes;
从“React”导入React;
从“react router dom”导入{HashRouter、Route、Switch、Redirect、Link};
从“/components/Main/Main.component”导入Main;
从“./components/SecondView/SecondView.component”导入SecondView;
从“./components/ThirdView/ThirdView.component”导入ThirdView;
从“./components/Traineeship/traineeships.component”导入培训课程;
从“/components/information/information filter.component”导入InformationFilter;
从“/components/information/information job.component”导入InformationJob;
类AppRoutes扩展了React.Component{
建造师(道具){
超级(道具);
此.state={
选定的行业:“”,
所选作业:“”,
行业:[],
职位:[],
}
}
render(){
const InformationFilterPage=()=>;
const InformationJobPage=()=>;
const TraineeshipPage=()=>;
返回(
);
}
}
导出默认批准;
有人知道这里发生了什么吗?
由于交叉传递的值,我将状态保留在这个组件中,您可能会说为什么不使用redux,但问题是我不想用于这个项目,因为它是一个非常小的项目 当您通过setRootState对父组件调用setState时,它会设置父组件的状态,intern会导致其子组件的重新加载,这会导致子组件重新装载,调用componentDidMount,然后再次在父组件上设置状态,循环继续 要解决这个问题,您可以调用api并在父组件本身中设置状态 您的父组件现在应该具有
componentDidMount() {
this.industryApiCall ()
}
industryApiCall = () => {
industryApi.getAll().then(response => {
if (response.data) {
this.props.setState({
industries: response.data._embedded.industries
})
} else {
console.log(response)
}
})
}
你可以像这样把这个函数传递给你的孩子
const InformationFilterPage = () => <InformationFilter rootState={this.state}
callApi={this.industryApiCall.bind(this)} />;
const InformationFilterPage=()=>;
并通过呼叫将其用于您的孩子组件中
this.props.callApi()
当您通过setRootState调用父组件上的setState时,它会设置父组件的状态,intern会导致其子组件的重新加载,从而导致子组件重新装载调用com的组件