react初學(xué)者，有個問題不清楚：
點(diǎn)擊按鈕，執(zhí)行this.calcAccount();

1.通過refs獲取到子組件，并調(diào)用其實(shí)例方法test(),為什么會undefined呢？
注意點(diǎn):此子組件是被Form.create()(ElectricityTemp)包裝過，這是antdesign中的From組件提供的方法。
以下兩個組件，去除了不必要的code.

父組件:ElectricityFees.tsx

class ElectricityFees extends React.Component<Iprops, Istate> {

    constructor(props: any) {
        super(props);
        this.calcAccount = this.calcAccount.bind(this);
    }

    public calcAccount: (e: any) => void = (e: any) => {
        const self = this;
        this.props.rooms.forEach((_:object, i:number) => {
            const a = self[`refs${i}`].current; **// 這里a是子組件，可是為什么沒有test方法?**
            a.test();
        });
    };


    public render() {
        const key: string = 'name';
        this.props.rooms.forEach((_:object, i:number) => {
            this[`refs${i}`] = React.createRef();
        });

        return (

            <React.Fragment>
                <Row gutter={24}>
                    {
                        this.props.rooms.map((_: object, i: number) => {
                            return (
                                <Col className="gutter-row" span={6} key={i}>
                                    <WrappedTimeRelatedForm name={_[key]} ref={this[`refs${i}`]}/>
                                </Col>
                            )
                        })
                    }
                </Row>
                <Button onClick={this.calcAccount}>結(jié)算</Button>
            </React.Fragment>
        )
    }
}

export default ElectricityFees;

子組件：WrappedTimeRelatedForm.tsx

class ElectricityTemp extends React.Component<Iprops, any> {

     public test(){
            console.log(this.props.name);
     }
    public render() {
        return (
            <Form>
                ...
            </Form>
        );
    }
}


const WrappedTimeRelatedForm = Form.create()(ElectricityTemp);

export default WrappedTimeRelatedForm;