react中能够触发重新渲染的只有setState；而所谓的props的变化会引起重新渲染只是一个“表象”，因为一旦你...
//Parent.js class Parent extends React.Component { constructor(props) { super(props); ...
class UserInput extends React.Component { state = { user: this.props.user } handleChange = (e) => { this.setState({ user: { ...this.state.user, name: e.target.value } }); } render() { const { onConfirm } = this.props; const { user } = this.state; return ( { onCo...
方法二:利用ref父组件调用子组件函数(不符合react设计规范,但可以算一个逃生出口嘻嘻～) classfatherextends Component { constructer(props) { super(props);this.state={ a: '1', b: '2', }this.myRefthis.test =this.test.bind(this) } change() { const { a,b } = this.state console.log(this...
classUserInputextendsReact.Component{state={user:this.props.user}handleChange=(e)=>{this.setState({user:{...this.state.user,name:e.target.value}});}render(){const{onConfirm}=this.props;const{user}=this.state;return({onConfirm(user)}}>确定);}}classAppextendsReact.Component{state={users...
class A extends React.Component{ constructor(props){ super(props) this.state = { user: { name: 'frank', age: 18 } } } change = () => { const user = Object.assign({}, this.state.user) user.name = 'jack' this.setState((state) => ({ user: user })) ...
export default class ChildToFaDemo extends React.Component { changeProps (data) { console.log(this, data) this.props.changeData(data) } render () { return ( {this.props.data} 修改 ) }}// App.jsximport React from 'react'import ChildToFaDemo from './ChildToFa'export default...
this.setState((prevState,props)=>{return{num:prevState.counter+1};}); 完整的修改函数是: importReact,{Component}from'react';importReactDOMfrom'react-dom';classAppextendsComponent{state={num:0};changeTitle=()=>{this.setState((prevState,props)=>{return{num:prevState.num+1}});};render(){re...
要通讯的子组件只需通过props接收状态或操作状态的方法 // 父组件classParent extends React.Component{// 父组件提供状态state={message:'父组件的message'}// 提供修改状态的方法changeMsg=()=>{this.setState({message:this.state.message+'哈哈哈哈哈'})}render(){return(<Child1 msg={this.state.message}...
正式看 updateClassComponent 方法,惯例删去一些DEV环境代码。 // react-reconciler\src\ReactFiberBeginWork.jsfunctionupdateClassComponent(current:Fiber|null,workInProgress:Fiber,Component:any,nextProps,renderExpirationTime:ExpirationTime,){// Push context providers early to prevent context stack mismatches.// ...