我正在尝试将孩子的状态归为父。将Child的状态和方法移到父级后,我得到以下信息:
export default class Parent extends React.Component {
constructor() {
super();
this.state = { mpc_steps: { price: 0, credits: 0, text: "MPC Credits" } }
}
setMPCSteps = () => {
let step = this.refs.mpc_slider.instance.getVal(); // Will fail
this.setState({
mpc_steps: {
price: step * 200,
credits: step,
text: "MPC Credits"
}
});
};
render() {
return(
<div>
<Child getCredits={this.setMPCSteps} getParentState={this.state.mpc_steps}/>
)
}
}
子组件:
export default class Child extends React.Component {
render() {
return (
<Fragment>
<mobiscroll.Slider
ref="mpc_slider"
value={this.props.getParentState}
onChange={this.props.getCredits}
>
Buy Credits @ $2/Credit
</mobiscroll.Slider>
</Fragment>
)
}
}
我需要以某种方式从父级调用子级的ref值。问题在于,mobiscroll ref不是从父级定义的。有一个简单的方法吗?欢迎任何提示。
答案 0 :(得分:1)
您可以使用React.forwardRef
api:
子组件:
class Child extends React.Component {
render() {
return (
<Fragment>
<mobiscroll.Slider
ref={this.props.innerRef}
value={this.props.getParentState}
onChange={this.props.getCredits}
>
Buy Credits @ $2/Credit
</mobiscroll.Slider>
</Fragment>
)
}
}
export default React.forwardRef((props, ref) => <Child innerRef={ref} {...props}/>);
并像这样使用它:
<Child ref="mpc_slider" />