react 获取 ref

class Child extends React.Component{

constructor(props){

super(props);

this.myRef=React.createRef();

}

componentDidMount(){

console.log(this.myRef.current);

}

render(){

return <input ref={this.myRef}/>

}

}

第二种方法

<input ref={(input) => {this.textInput = input;}} type="text" />