javascript - react 。 onCopy 事件的 preventDefault() 不起作用

Question

我想弄清楚如何让剪贴板事件在 onCopy 事件上返回 false。我用于测试 onCopy 处理程序和 e.preventDefault() 方法。但是文本被复制到缓冲区没有障碍!我想念什么？

提前致谢。

import React from 'react';
import ReactDOM from 'react-dom';
import PropTypes from 'prop-types';
import ReactDOMServer from 'react-dom/server';
import './index.css';


class Copy extends React.Component {
  constructor(props) {
    super(props);

    this.state = {
      time: '',
      timer: false,
      counter: 0
    };

    this.handlerCopy = this.handlerCopy.bind(this);
  }

  handlerCopy(e) {

    e.preventDefault(); // must prevent the current event

    this.setState(prevState => ({
      counter: prevState.counter + 1
    }));

    alert('Don\'t copy it!');
  }

  render() {
    return (
      <React.Fragment>
        <p onCopy={this.handlerCopy}>Copy me!</p>
        <p>Copy count: {this.state.counter}</p>
      </React.Fragment>
    );
  }
}

ReactDOM.render(
<Copy />,
document.getElementById('root'));

Answer 1

这真是个好问题!

发生这种情况是因为 React 的实际事件监听器也在文档的根部，这意味着点击事件已经冒泡到根部。您可以使用 e.nativeEvent.stopImmediatePropagation() 来阻止其他事件监听器。

试一试:

import React from 'react';
import ReactDOM from 'react-dom';
import PropTypes from 'prop-types';
import ReactDOMServer from 'react-dom/server';
import './index.css';


class Copy extends React.Component {
  constructor(props) {
    super(props);

    this.state = {
      time: '',
      timer: false,
      counter: 0
    };

    this.handlerCopy = this.handlerCopy.bind(this);
  }

  handlerCopy(e) {
    console.log(e.target.innerHTML);
    e.preventDefault();
    e.nativeEvent.stopImmediatePropagation();

    this.setState(prevState => ({
      counter: prevState.counter + 1
    }));

    alert('Don\'t copy it!');
  }

  render() {
    return (
      <React.Fragment>
        <p onCopy={this.handlerCopy}>Copy me!</p>
        <p>Copy count: {this.state.counter}</p>
      </React.Fragment>
    );
  }
}

ReactDOM.render(
<Copy />,
document.getElementById('root'));