反应 onScroll 不起作用 [英] React onScroll not working

问题描述

我正在尝试将 onscroll 事件处理程序添加到特定的 dom 元素.看看这段代码:

class ScrollingApp 扩展 React.Component {..._handleScroll(ev) {console.log("滚动！");}componentDidMount() {this.refs.list.addEventListener('scroll', this._handleScroll);}componentWillUnmount() {this.refs.list.removeEventListener('scroll', this._handleScroll);}使成为() {返回 (<div ref="列表">{this.props.items.map( (item) => {return (<Item item={item}/>);})}

);}}

代码很简单，正如你所看到的，我想处理 div#list 滚动.当我运行这个例子时，它不起作用.所以我尝试直接在渲染方法上绑定 this._handleScroll ，它也不起作用.

... </div>

所以我打开了 chrome 检查器，直接添加了 onscroll 事件:

document.getElementById('#list').addEventListener('scroll', ...);

它正在工作！我不知道为什么会发生这种情况.这是 React 的错误还是什么?还是我错过了什么?任何设备都将不胜感激.

解决方案

问题的根源在于 this.refs.list 是一个 React 组件，而不是一个 DOM 节点.要获取具有 addEventListener() 方法的 DOM 元素，您需要调用 ReactDOM.findDOMNode():

class ScrollingApp 扩展 React.Component {_handleScroll(ev) {console.log("滚动！");}componentDidMount() {const list = ReactDOM.findDOMNode(this.refs.list)list.addEventListener('scroll', this._handleScroll);}componentWillUnmount() {const list = ReactDOM.findDOMNode(this.refs.list)list.removeEventListener('scroll', this._handleScroll);}/* .... */}

I'm trying to add onscroll event handler to specific dom element. Look at this code:

class ScrollingApp extends React.Component {
    ...
    _handleScroll(ev) {
        console.log("Scrolling!");
    }
    componentDidMount() {
        this.refs.list.addEventListener('scroll', this._handleScroll);
    }
    componentWillUnmount() {
        this.refs.list.removeEventListener('scroll', this._handleScroll);
    }
    render() {
        return (
            <div ref="list">
                {
                    this.props.items.map( (item) => {
                        return (<Item item={item} />);
                    })
                }
            </div>
        );
    }
}

Code is quite simple, and as you can see, I want to handle div#list scrolling. When I was running this example, it isn't working. So I tried bind this._handleScroll on render method directly, it doesn't work either.

<div ref="list" onScroll={this._handleScroll.bind(this)> ... </div>

So i opened chrome inspector, adding onscroll event directly with:

document.getElementById('#list').addEventListener('scroll', ...);

and it is working! I don't know why this happens. Is this a bug of React or something? or did I missed something? Any device will very appreciated.

解决方案

The root of the problem is that this.refs.list is a React component, not a DOM node. To get the DOM element, which has the addEventListener() method, you need to call ReactDOM.findDOMNode():

class ScrollingApp extends React.Component {

    _handleScroll(ev) {
        console.log("Scrolling!");
    }
    componentDidMount() {
        const list = ReactDOM.findDOMNode(this.refs.list)
        list.addEventListener('scroll', this._handleScroll);
    }
    componentWillUnmount() {
        const list = ReactDOM.findDOMNode(this.refs.list)
        list.removeEventListener('scroll', this._handleScroll);
    }
    /* .... */
}

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