javascript – 如何将事件传递给setState回调函数?

在React中是否可以将外部事件传递给setState的回调函数?

someFunc(event) { 
    this.setState(
        {
            value: event.target.value
        },
        () => {                 
            this.props.onChange(event);    // <- cannot pass to here                
        }
    );
}

编辑:请参阅Liam的下面接受的解决方案,以获得优秀的答案,
以下是我的问题的具体解决方案:

someFunc(event) { 
    event.persist() // <- add this line and event should pass without a problem
    this.setState(
        {
            value: event.target.value
        },
        () => {                 
            this.props.onChange(event);                 
        }
    );
}

解决方法:

您需要提取值或使用e.persist()

https://reactjs.org/docs/events.html#event-pooling

class App extends React.Component {

something = (value) =>{
  {console.log(value, 'coming from child')}
}
  render() {

    return (
      <div >
        <Hello text={this.something} />
      </div>
    );
  }
}


class Hello extends React.Component {

  constructor() {
    super()
    this.state = {
      value: ''
    }
  }
  onChange = (e) => {
    const value = e.target.value;
    this.setState({ value }, () => {
    
      this.props.text(value)
    })
  }
  render() {

    return (
      <div style={{ padding: 24 }}>
        <input onChange={this.onChange} value={this.state.value} />

      </div>
    );
  }
}



ReactDOM.render(<App />, document.getElementById('root'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>

<div id='root' ></div>

或者如果你打算传递值状态,你可以在回调中使用this.state.value它将起作用.

someFunc(event) { 
    this.setState(
        {
            value: event.target.value
        },
        () => {                 
            this.props.onChange(this.state.value);    // <- this should work                
        }
    );
}
上一篇:react数据管理


下一篇:(六)React表单详解