小编Huz*_*med的帖子

class Bills extends Component {
constructor(props) {
    super(props)
    this.state = {
        productName: '',
        price: 0,
        quantity: 0,
        noOfProductsField: 0
    }
}
handleChange = name => event => {
    this.setState({
        [name]: event.target.value,
    });
};

createFields = () => {
        const { classes } = this.props;
        let children = []
        for (let i = 0; i < this.state.noOfProductsField; i++) {
            children.push(
                <div>
                    <Select
                        className={classes.textField}
                         value = { this.state[i] }
                    onChange={this.handleChange('productName')}
                        displayEmpty
                        SelectProps={{
                            MenuProps: {
                                className: classes.menu,
                            }
                        }}>
                        <MenuItem value="" disabled>
                            Select …