This article brings you an introduction to React component communication (code examples). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
I have been free to study the React framework by myself recently. All the problems and experiences during the self-study process will be recorded here. I hope it can help students who are learning the React framework. Without further ado, let’s talk about the code.
First pass from parent to child:
import React, { Component } from 'react'; import Com1 from './componments/com1' class App extends Component { constructor(props){ super(props) this.state = { arr: [{ "userName": "fangMing", "text": "123333", "result": true }, { "userName": "zhangSan", "text": "345555", "result": false }, { "userName": "liSi", "text": "567777", "result": true }, { "userName": "wangWu", "text": "789999", "result": true },] }; this.foo = "我来自父组件" //这个也是父传子方法,可能初学者有点迷,刚开始我也用来和arr = {this.state.arr}做区分 }; render() { return ( <div> <header> <img alt="Introduction to React component communication (code example)" > </header> <com1></com1> </div> ); } } export default App;
Child component:
import React, { Component } from 'react'; class Ele extends Component{ constructor(props){ super(props) }; render(){ return ( <div> <h1>Hello, {this.props.age}</h1> <p>{this.props.fn}</p> <ul> { this.props.arr.map(item => { //这个地方通过this.props.arr接收到父组件传过来的arr,然后在{}里面进行js的循环 return ( <li> {item.userName} 评论是:{item.text} </li> ) }) } </ul> </div> ); }; } export default Ele;
The result shows:
The above is the parent The main method of passing values to children is to use props to pass values. Let’s take a look at passing from child to parent.
Passing from child to parent:
First is the child component:
import React, { Component } from 'react'; class Ele extends Component{ constructor(props){ super(props); this.state = ({ childText: "我来自子组件" }) }; clickFun(text) { //定义触发的方法 this.props.pfn(text)//这个地方把值传递给了props的事件当中 } render(){ return ( <div> {/* 通过事件进行传值,如果想得到event,可以在参数最后加一个event, 这个地方还是要强调,this,this,this */} <button> 传值 </button> </div> ); }; } export default Ele;
Parent component:
import React, { Component } from 'react'; import Com1 from './componments/com1' class App extends Component { constructor(props){ super(props) this.state = { parentText: "现在是父组件", }; fn(data) { this.setState({ parentText: data //把父组件中的parentText替换为子组件传递的值 },() =>{ console.log(this.state.parentText);//setState是异步操作,但是我们可以在它的回调函数里面进行操作 }); }; render() { return ( <div> <com1></com1> {/*通过绑定事件进行值的运算,这个地方一定要记得.bind(this),不然会报错,切记切记,因为通过事件传递的时候this的指向已经改变 */} <p>text is {this.state.parentText}</p> </div> ); } } export default App;
The above is the method of value transfer between parent and child components. Please correct me if there are any mistakes
I haven’t learned about value transfer between sibling components yet. I will update it after learning about value transfer between sibling components
[Related recommendations: React video tutorial]
The above is the detailed content of Introduction to React component communication (code example). For more information, please follow other related articles on the PHP Chinese website!