thought

In the world of react, all state changes (data changes) drive dom changes. Dynamic addition of dom does not append a < li > or a < td > like jquery before, but dynamically adds dom by loading < li > or < td > data array []. The following example implements the use of antd's component library.
Reference resources: https://ant.design/components/form-cn/#components-form-demo-dynamic-form-item

Example

Realization

1. Quotes

import React, { Component, PropTypes } from 'react';
import { Form, Input, Radio, Row, Col, Upload, Icon, Button, message, Select, DatePicker,Modal} from 'antd';

2. initialization

constructor(props) {
      super(props);
       this.state = {
           hover: [],
       };
}

3. Content components
The content component is actually a < UL > < Li >, traversing an < li > array articleContent, and the CSS style is shown at the end.

render(){

const liClass = this.state.hover[index] ? "rectanglesON " : "rectanglesOFF ";
const formItems = this.state.articleData.articleContent.map((k, index) => {
return (
<li key={index} ref={"li_" + index} datatype={k.contentType} className={liClass} onMouseEnter={this.handleMouseEnter.bind(this,index)} onMouseLeave{this.handleMouseLeave.bind(this,index)} 
onClick={this.handleClickByModule.bind(this,index,k.contentType)}>
    //What the business needs to show
    <div>li What to show on the label</div>
    //Button in the lower right corner when hovering
    <div className={this.state.hover[index]?'actionShow':'actionHide'}>
        <div className={(index > 0)?'domShow':'domHide'}>
            <Button type="primary" size="small" className="mr-5" onClick={this.handleClickBySortUp.bind(this,index)}><Icon type="caret-up" />Move upward</Button>
        </div>
        <div className={(index < this.state.articleData.articleContent.length - 1)?'domShow':'domHide'}>
            <Button type="primary" size="small" className="mr-5" onClick={this.handleClickBySortDown.bind(this,index)}><Icon type="caret-down" />Move down</Button>
        </div>
        <div>
            <Button type="primary" size="small" className="mr-5" onClick={this.handleClickByDelete.bind(this,index)}><Icon type="delete" />delete</Button>
        </div>
    </div>
</li>
)
});

//ul
return (
    <FormItem label="content">
        <ul className='listContent'>
            {formItems}
        </ul>
    </FormItem>
    )
}

4. incident

//Events triggered when the mouse moves over the content module
    handleMouseEnter(key) {
        let arg = this.state.hover;
        arg[key] = true;
        this.setState({
            hover: arg
        });
    }

    //Events triggered when the mouse leaves the content module
    handleMouseLeave(key) {
        let arg = this.state.hover;
        arg[key] = false;
        this.setState({
            hover: arg
        });
    }
    //Click the Up Sort button event
    handleClickBySortUp(index, e) {
        e.stopPropagation();
        let arr = this.state.articleData.articleContent;
        if (index != 0) {
            let temp = arr[index - 1];
            arr[index - 1] = arr[index];
            arr[index] = temp;
            this.setState({
                articleData: this.state.articleData,
            });
        }
    }

    //Click the Down Sort button event
    handleClickBySortDown(index, e) {
        e.stopPropagation();
        let arr = this.state.articleData.articleContent;
        if (index != arr.length) {
            let temp = arr[index + 1];
            arr[index + 1] = arr[index];
            arr[index] = temp;
            this.setState({
                articleData: this.state.articleData,
            });
        }
    }

    //Click the Delete button event
    handleClickByDelete(index, e) {
        e.stopPropagation();
        let arr = this.state.articleData.articleContent;
        arr.splice(index, 1);
        this.setState({
            articleData: this.state.articleData,
        });
    }

5.CSS style

.rectanglesON {
    word-wrap: break-word;
    min-height: 200px;
    border: 1px dashed #808080;
    list-style-type: none;
    margin-bottom: 10px;
    cursor: pointer;
}

.rectanglesOFF {
    word-wrap: break-word;
    min-height: 200px;
    border: 1px dashed #d3d3d3;
    list-style-type: none;
    margin-bottom: 10px;
}

.listContent li {
    position: relative;
    .actionShow {
        position: absolute;
        bottom: 0;
        right: 0;
        padding-left: 10px;
        display: flex;
    }
    .actionHide {
        position: absolute;
        bottom: 0;
        right: 0;
        padding-left: 10px;
        display: none;
    }
}

.mr-5{
    margin-right:5px;
}