转发状态 vs 转发道具到子组件

我在将状态从父组件转发到子组件时遇到问题，这两个组件是类组件。将状态从父组件转发到子组件时，我想在子组件中使用 state showModal 变量作为显示状态变量：

 this.state = {
     show: this.props.show
 }

此变量用于激活模态。当我将它用作 this.props.show 时，状态已被转发到子组件并更新，但是当我在子组件中使用 this.state 中的道具时，它尚未更新。有谁知道问题出在哪里？

第一 - 父组件：

    import React, { Component } from 'react';
    import Modal from './UI/Modal';

    class EnteredBooks extends Component {
        constructor(props) {
            super(props)

            this.state = {
                enteredBook: this.props.enteredBook,
                showModal: false
            }
        }

        detailsHandler = () => {
            this.setState({
                showModal: true
            })
        }

        render() {
            let show =  this.state.showModal;
            return (
                <div>
                     <div className="product">
                         <img src="{this.props.enteredWatch.bookUrl}" />
                         <p>{this.props.enteredWatch.bookType}</p>
                         <p>euro{this.props.enteredWatch.bookPrice}</p>
                         <button 
                             className="details-button"
                             onClick={this.detailsHandler}
                                >
                                    Details
                         </button>
                         <Modal show={this.state.showModal} watch={this.state.enteredWatch} />
                         <button className="buy-button">Buy</button>
                      </div>
                </div>
            );
        }
    }

export default EnteredWatches;

第二 - 子组件：

import React, {Component} from 'react';
import classes from './Modal.css';

class Modal extends React.Component {
constructor(props) {
    super(props)

        this.state = {
            book: this.props.book,
            show: this.props.show
        }
    }
return(
        <div>
             <div className="Modal"
                    style={{
                        transform: this.state.show ? 'translateY(0)' : 'translateY(-100vh)',
                        opacity: this.state.show ? '1':'0'
                    }}>

                    <img src={this.state.book.bookUrl} />
                    <p>{this.state.book.bookType}</p>
                    <p>{this.state.book.watchUrl}</p>
                    <button className="details-button">Details</button>
                    <button className="buy-button">Buy</b
                </div>
            </div>
        );
    }
}


export default Modal;