为什么我的 onClick 在渲染时被调用?- React.js

问题描述

我创建了一个组件:

类创建扩展组件{构造函数(道具){超级(道具)；}使成为() {var playlistDOM = this.renderPlaylists(this.props.playlists);返回 (
{播放列表DOM}</div>)}激活播放列表(播放列表 ID){调试器；}渲染播放列表(播放列表){返回播放列表.map(播放列表 => {return <div key={playlist.playlist_id} onClick={this.activatePlaylist(playlist.playlist_id)}>{playlist.playlist_name}</div>});}}功能 mapStateToProps(状态){返回 {播放列表:state.playlists}}导出默认连接(mapStateToProps)(创建)；

当我 render 这个页面时，activatePlaylist 会为我的 map 中的每个 playlist 调用.如果我 bind activatePlaylist 喜欢:

activatePlaylist.bind(this, playlist.playlist_id)

我也可以使用匿名函数:

onClick={() =>this.activatePlaylist(playlist.playlist_id)}

然后它按预期工作.为什么会这样?

解决方案

你需要传递给 onClick reference 才能起作用，当你这样做 activatePlaylist(..) 您调用函数并传递给从 activatePlaylist 返回的 onClick 值.您可以使用以下三个选项之一:

1.使用 .bind

activatePlaylist.bind(this, playlist.playlist_id)

2.使用箭头函数

onClick={ () =>this.activatePlaylist(playlist.playlist_id) }

3.或从 activatePlaylist

返回函数

activatePlaylist(playlistId) {返回函数(){//你编码}}

I have a component that I have created:

class Create extends Component {
  constructor(props) {
    super(props);
  }

  render() {
    var playlistDOM = this.renderPlaylists(this.props.playlists);
    return (
      <div>
        {playlistDOM}
      </div>
    )
  }

  activatePlaylist(playlistId) {
    debugger;
  }

  renderPlaylists(playlists) {
    return playlists.map(playlist => {
      return <div key={playlist.playlist_id} onClick={this.activatePlaylist(playlist.playlist_id)}>{playlist.playlist_name}</div>
    });
  }
}

function mapStateToProps(state) {
  return {
    playlists: state.playlists
  }
}

export default connect(mapStateToProps)(Create);

When I render this page, activatePlaylist is called for each playlist in my map. If I bind activatePlaylist like:

activatePlaylist.bind(this, playlist.playlist_id)

I can also use an anonymous function:

onClick={() => this.activatePlaylist(playlist.playlist_id)}

then it works as expected. Why does this happen?

解决方案

You need pass to onClick reference to function, when you do like this activatePlaylist( .. ) you call function and pass to onClick value that returned from activatePlaylist. You can use one of these three options:

1. using .bind

activatePlaylist.bind(this, playlist.playlist_id)

2. using arrow function

onClick={ () => this.activatePlaylist(playlist.playlist_id) }

3. or return function from activatePlaylist

activatePlaylist(playlistId) {
  return function () {
     // you code
  }
}

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