How to add scroll event in react component

Question

I\'m trying to add an onScroll event on a table. This is what I\'ve tried:

componentDidMount() {
    ReactDOM.findDOMNode(this.refs.table).addEv         


        

Answer 1

Give this a try, added .bind(this) to this.listenScrollEvent when you pass it to the addEventListener.

   componentDidMount() {
        ReactDOM.findDOMNode(this.refs.table).addEventListener('scroll', this.listenScrollEvent.bind(this));
    }

    componentWillUnmount() {
        ReactDOM.findDOMNode(this.refs.table).removeEventListener('scroll', this.listenScrollEvent.bind(this));
    }

    listenScrollEvent() {
        console.log('Scroll event detected!');
    }

    render() {
        return (
            <table ref="table">
               [...]
            </table>
        )
    }

Answer 2

You can use onScroll attribute:

listenScrollEvent() {
    console.log('Scroll event detected!');
}

render() {
    return (
        <table onScroll={this.listenScrollEvent}>
           [...]
        </table>
    )
}

Here is an example: https://jsfiddle.net/81Lujabv/

Answer 3

You need to bind this to the element in context.

render() {
    return (
        <table ref="table" onScroll={this.listenScrollEvent.bind(this)}>
           [...]
        </table>
    )
}

Answer 4

according to React documents(https://reactjs.org/docs/handling-events.html),

React events are named using camelCase, rather than lowercase. You can set attributes as you do with pure HTML.

HTML:

<div onclick="..." onscroll="...">
  ...
</div>

JSX:

<div onClick={...} onScroll={...}>
  ...
</div>

you should create a wrapper block element which has fixed height to enable scroll.

Answer 5

I had been finding a good solution to this problem. The following piece of code is working, where the listener is just on the particular class/div : React version is 16.0.0

First import ReactDOM, import ReactDOM from "react-dom";

Then in the class xyz extends Component section

  constructor(props) {
    super();
    this.state = {
        vPos : 0
    }
    this.listenScrollEvent = this.listenScrollEvent.bind(this);
  }

  componentDidMount() {
    ReactDOM.findDOMNode(this.refs.category_scroll).addEventListener('scroll', this.listenScrollEvent);
  }

  componentWillUnmount() {
      ReactDOM.findDOMNode(this.refs.category_scroll).removeEventListener('scroll', this.listenScrollEvent);
  }

  listenScrollEvent(event) {
    console.log('firee');
    this.setState({
        vPos: event.target.body.scrollTop
    });
  }

After pasting the above functions, in the render() method , whatever you want to name the ref method, you can do so, make sure the same name goes in the findDOMNode as well , i.e, findDOMNode(this.refs.category_scroll):

<div onScroll={this.listenScrollEvent} ref="category_scroll">
...
</div>

---

.

.

If it's a horizontall scroll, then event.currentTarget.scrollTop works in the listenScrollEvent() function.

Answer 6

I was looking to do something similar. Adding the event listener to the window instead of the ReactDom.findDOMNode worked for me...

componentDidMount() {
    window.addEventListener('scroll', this.handleScrollToElement);
}

componentWillUnmount() {
    window.removeEventListener('scroll', this.handleScrollToElement);
}

handleScrollToElement(event) {
    console.log('Fired ' + event)
}