相关疑难解决方法(0)

我正在从teamtreehouse.com制作一个非常基本的React应用程序,而且我经常遇到

"TypeError:无法读取未定义的属性'onPlayerScoreChange'"

即使我正确绑定我的功能(我认为)

'onPlayerScoreChange'Grandparent组件中的一种方法,当用户点击"+"或" - "按钮更改玩家的分数时执行该方法.

如果有人可以解释错误,那将是非常有帮助的,因为我认为我正在设置this.onPlayerScoreChange = this.onPlayerScoreChange.bind(this)伟大的祖父母的构造函数.

父组件:

class App extends React.Component {
constructor(props) {
    super(props);
    this.onPlayerScoreChange = this.onPlayerScoreChange.bind(this)
    this.state = {
        initialPlayers: props.initialPlayers,
    };
}

onPlayerScoreChange(delta, index) {
    this.setState((prevState, props) => {
        return {initialPlayers: this.prevState.initialPlayers[index].score += delta}
    })
}

render() {
    return(
        <div className = "scoreboard">
            <Header title = {this.props.title}/>
            <div className = "players">
                {this.state.initialPlayers.map(function(player, index) {
                    return(
                        <Player 
                        name = {player.name} 
                        score = {player.score} 
                        key = {player.id} 
                        index = {index}
                        onScoreChange = …