添加到数组中 })); } render() { return ( <div> {this.state.components.map(component => component)} <button onClick={this.addComponent}>添加组件</button> </div> ); } } class ChildComponent extends Component { render() { return <div>子组件</div>; } } export default ParentComponent...
= () => { const [showComponent, setShowComponent] = useState(false); const handleClick = () => { setShowComponent(true); }; return ( <div> <button onClick={handleClick}>点击加载组件</button> {showComponent && <MyComponent />} </div> ); }; export default ParentComponent; ...
item 1')}>Add Item 1</button> <button onClick={() => addItem('item 2')}>Add Item 2</button> <ul> {cart.map((item, index) => { return ( <li key={index}> {item} <button onClick={() => removeItem(index)}>Remove</button> </li> ) })} ...
="button" value="递增" onClick={ this.fnAdd } /> 30 </div> 31 ) 32 } 33 } 34 ReactDOM.render(<Increase />,document.getElementById("root"));2,案例:选项卡1 <div id="root"></div> 2 <script type="text/babel"> 3 class Tab extends React.Component{ 4 constructor(props){...
import {useState} from "React" const TestOneComponent = ({value}) => ( <span>{value.toString()}<span> ) const TestTwoComponent = ({value, onClick}) => ( <span>{value.toString()}</span> <button onClick={onClick}>Increase Value</button> ) const ParentComponent = () => { const...
class Person extends Component { addPerson_onClick= ()=>{ const name=this.nameNode.value const age=this.ageNode.value constpersonObj= {id:nanoid(), name, age} this.props.jiaYiRen(personObj)} render() {return(<div> <h2>我是Person组件,上方组件求和为{this.props.he}</h2>// <--- 共...
function MyButton() { const [count, setCount] = useState(0); function handleClick() { setCount(count + 1); } return ( <button onClick={handleClick}> Clicked {count} times </button> ); } React will call your component function again. This time, count will be 1. Then it will be...
importReactfrom'react';classStateextendsReact.Component{constructor() {super();this.state={count:0, } }render() {return<div><p>count: {this.state.count}</p><buttononClick={()=>this.setState({count:this.state.count+1}) }>类组件计数</button></div>} ...
<button onClick={changeHot}>变天</button> </div> )} 三、useEffect副作用钩子 useEffect 就是一个 Effect Hook，可以让你在函数组件中执行副作用操作。useEffect可以告诉 React 组件需要在挂载完成、更新完成、卸载前执行某些操作。它跟 class 组件中的componentDidMount、componentDidUpdate 和 componentWillUnmount...
(time + 1); }, 5000); } const getDOm = function(){ // 我们可以毫无负担的获取到domRef节点,不受函数组件重复执行的影响 console.log(domRef) } return ( <div ref={domRef}> <p>{time}</p> <button onClick={click}>add</button> <button onClick={getDOm}>getDom</button> </div> )...