反应:"this"在组件函数中未定义 [英] React: "this" is undefined inside a component function
本文介绍了反应:"this"在组件函数中未定义的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
class PlayerControls extends React.Component {
constructor(props) {
super(props)
this.state = {
loopActive: false,
shuffleActive: false,
}
}
render() {
var shuffleClassName = this.state.toggleActive ? "player-control-icon active" : "player-control-icon"
return (
<div className="player-controls">
<FontAwesome
className="player-control-icon"
name='refresh'
onClick={this.onToggleLoop}
spin={this.state.loopActive}
/>
<FontAwesome
className={shuffleClassName}
name='random'
onClick={this.onToggleShuffle}
/>
</div>
);
}
onToggleLoop(event) {
// "this is undefined??" <--- here
this.setState({loopActive: !this.state.loopActive})
this.props.onToggleLoop()
}
我想在切换时更新loopActive
状态,但是在处理程序中未定义this
对象.根据教程文档,我this
应该引用该组件.我想念什么吗?
I want to update loopActive
state on toggle, but this
object is undefined in the handler. According to the tutorial doc, I this
should refer to the component. Am I missing something?
推荐答案
ES6 React.Component
不会自动将方法绑定到自身.您需要将它们自己绑定在constructor
中.像这样:
ES6 React.Component
doesn't auto bind methods to itself. You need to bind them yourself in constructor
. Like this:
constructor (props){
super(props);
this.state = {
loopActive: false,
shuffleActive: false,
};
this.onToggleLoop = this.onToggleLoop.bind(this);
}
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