反应 ref.example.value 与 e.target.value

Question

我有下面的组件可以正常工作，但是如果我只是代替this.refs.searchString.value它会工作吗？event.target.value如果是这样，哪一种是首选方法？各自的优点和缺点是什么？

const SearchBar = React.createClass({

  handleSubmit (event) {
    event.preventDefault()
    const formattedSearchString = this.refs.searchString.value.replace(/[^a-z]/gi, "").toLowerCase()
    this.refs.searchString.value = ''
    this.props.submitSearch(formattedSearchString)
  },
  render() {
    return (
      <form className="form form-group has-info col-md-4 text-align-center" onSubmit={this.handleSubmit}>
        <input className="search-input form-control" type="text" ref="searchString"  placeholder=" . . . enter pokemon name" />
        <button className="btn btn-info btn-raised" type="submit" name="button">Search!</button>
      </form>
    )
  }
})

Answer 1

正如文档中提到的，我们不应该过度使用 refs，首选方法是使用event.target.valueusing Controlled Components。

const SearchBar = React.createClass({
  getInitialState(){
     return {textValue: ""};
  },
  onTextChange(evt) {
     this.setState({textValue: evt.target.value});
  },
  handleSubmit (event) {
    event.preventDefault()
    const formattedSearchString = this.state.textValue.replace(/[^a-z]/gi, "").toLowerCase()
    this.refs.searchString.value = ''
    this.props.submitSearch(formattedSearchString)
  },
  render() {
    return (
      <form className="form form-group has-info col-md-4 text-align-center" onSubmit={this.handleSubmit}>
        <input className="search-input form-control" type="text" value={this.state.textValue} onChange={this.onTextChange}  placeholder=" . . . enter pokemon name" />
        <button className="btn btn-info btn-raised" type="submit" name="button">Search!</button>
      </form>
    )
  }
})