为什么以下代码不起作用?在此测试中,我只是尝试单击按钮时显示组件Board的状态。但我收到TypeError:undefined不是对象。
var board = (<Board/>);
return (
<View>
{ board }
<Button
title="Press me"
onPress={() => Alert.alert(board.state.lastRefresh)}
/>
</View>
);
};
Board组件具有以下构造函数:
constructor(props) {
super(props)
this.state = {
lastRefresh: Date(Date.now()).toString(),
}
...
答案 0 :(得分:0)
如果您的Board
组件是这样的:
import PageTwo from 'PageTwo';
export default class Board extends React.Component {
constructor(props) {
super(props);
this.state = {
lastRefresh: Date(Date.now()).toString(),
}
}
render() {
return (
<View>
<PageTwo lastRefresh={this.state.lastRefresh}>
</PageTwo>
</View>
)
}
}
您可以通过以下方式从PageTwo
组件中访问道具:
export default class PageTwo extends React.Component {
render() {
return (
<View>
<Button
title="Press me"
onPress={() => Alert.alert(this.props.lastRefresh)}
/>
</View>
)
}
}