Question

我有两个组件Display.jsx和DisplayList.jsx。组件协同工作以显示本地存储中的值。问题出在DisplayList.JSX handleDelete（）方法循环上。

我不明白为什么它会删除第一个元素而不是所选元素？以及如何解决？

Display.jsx

import {DisplayList} from './DisplayList';


class Display extends Component {
  constructor(props){
    let data = JSON.parse(localStorage.getItem('data'));
    super(props)
    this.state = {
      data: data,
  }

  // Methods
  this.displayValues = this.displayValues.bind(this);
  }

  displayValues(){

   return this.state.data.map((data1, index) =>
    <DisplayList
      key = {index}
      email = {data1.email}
      password = {data1.password}
      updateList = {this.updateList}
       /> 
    )
  }
  // This is the method that will be called from the child component.
  updateList = (data) => {
    this.setState({
      data
    });
  }
  render() {
    return (
      <ul className="list-group">
        {this.displayValues()}
      </ul>
    )
  }
}

export default Display;

DisplayList.jsx

import React, { Component } from 'react'
import {Button, Modal, Form} from 'react-bootstrap';


export class DisplayList extends Component {

    constructor(props){
        super(props)
        this.state = {
            email: '',
            password: '',
            show: false,
        };

        // Methods
        this.handleDelete = this.handleDelete.bind(this);
        this.onChange = this.onChange.bind(this);
    }

    onChange(event){
        this.setState({
            [event.target.name]: event.target.value
        })
    };   
    handleDelete(){
        const data = JSON.parse(localStorage.getItem('data'));
        for (let index = 0; index < data.length; index++) {
            if(this.props.email === data[index].email &&
                this.props.password === data[index].password){
                  console.log(this.props.email);
                  console.log(data[index]);
                data.splice(data[index], 1);
            }
            console.log('loop count');
        }
        localStorage.setItem('data', JSON.stringify(data));
        this.props.updateList(data);
    }


  render() {
    return (
    <div className = "mt-4">
        <li className="list-group-item text-justify">
            Email: {this.props.email} 
            <br /> 
            Password: {this.props.password}
            <br /> 
            <Button onClick = {this.handleShow} variant = "info mr-4 mt-1">Edit</Button>
            <Button onClick = {this.handleDelete} variant = "danger mt-1">Delete</Button>
        </li>
    </div>
    )
  }
}

Answer 1

代替：

data.splice(data[index], 1);

尝试重写整个数组：

data = [
    ...data.slice(0, index),
    ...data.slice(index + 1)
];

Answer 2

handleDelete(){
  const data = JSON.parse(localStorage.getItem('data'));
  const filteredData = data.filter(
      x => !(x.email === this.props.email && x.password === this.props.password)
   );
  localStorage.setItem('data', JSON.stringify(filteredData));
  this.props.updateList(filteredData);
}

如何删除所选元素反应

2 个答案: