Question

我是React的新手，这件事让我很困惑。我有一个具有数组的根组件，并且正在将功能ADD和DELETE作为道具传递给子组件 ui_forms 。在子组件中，我接受输入参数，并根据按下的按钮从数组中推送或删除数组。但是，我似乎不能多次执行推/删除操作，因为我想我在根组件中只注入了一次子组件。

有没有机会通过仅发送一次道具来执行用户想要的多次推入或删除操作？

谢谢

App.js

import FormsMap from './form_map';

class App extends Component {
  state = {
    maps : [
      {'regno' : 'Karan', 'id' : 1},
      {regno : 'Sahil', 'id' : 2},
      {'regno' : 'Rahul', id : 4},
      {regno : 'Mohit', id : 5},
      {regno : 'Kartik', id : 3}
    ]
  };

   function_as_props(list1) {
      console.log(this.state.maps);
      let ninja = [...this.state.maps];
      console.log(ninja);
      ninja.push({"regno" : list1, "id" : Math.random()*10});

      this.setState({
        maps : ninja 
      });
    console.log(ninja);


    function_as_props1(name) {
       let t = this.state.maps.indexOf(name);  
       let x = this.state.maps.splice(t,1);
       console.log(x);
       this.setState({
         maps : x
       });
       console.log(this.state.maps);
    }
  }

  render() {
      const p = this.state.maps.map(list => {
        return(
           <div key={list.id}> {list.regno} </div>
        );
       })

 return(
   <FormsMap transpose = {this.function_as_props.bind(this)}  traverse ={this.function_as_props1.bind(this)} /> <br />
 );


} 
}

export default app;

form_map.js

import React, { Component } from 'react';

class FormsMap extends Component {
    state = {
        name : null,
        age : null,
        hobby : null
    };

    changes(e) {
        this.setState({
            [e.target.id] : e.target.value
        });
    }

    handle = (e) => {
        e.preventDefault();
        console.log(this.state);
        this.props.transpose(this.state.name);
    }

    dels = (e) => {
        this.setState({
            [e.target.id] : e.target.value
        });
    }

    del_button(e) {
        e.preventDefault();
        //console.log(this.state.name);
        this.props.traverse(this.state.name);
    }
    render() {
        return(
            <React.Fragment>
            <form onSubmit={this.handle}>   {/* After entering all info, Press Enter*/}
                <label htmlFor="labels"> Name : </label>  
                <input type="text" id="name" placeholder="Your name goes here..." onChange={this.changes.bind(this)} />
                <label htmlFor="labels"> Age : </label>  
                <input type="text" id="age" placeholder="Your age goes here..." onChange={this.changes.bind(this)} />
                <label htmlFor="labels"> Hobby : </label>  
                <input type="text" id="hobby" placeholder="Your hobby goes here..." onChange={this.changes.bind(this)} /> <br /><br />
                <input type="submit" value="SUBMIT" /><br /><br />
            </form>

            <input type="text" id="name" placeholder="Enter name to delete..." onChange={this.dels} />   <button onClick={this.del_button.bind(this)}> DELETE </button>
            </React.Fragment>

        );
    }
}

export default FormsMap;

Answer 1

尝试一下

App.js

import React, { Component } from "react";
import FormsMap from "./components/FormsMap";

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      maps: [
        { regno: "Karan", id: 1 },
        { regno: "Sahil", id: 2 },
        { regno: "Rahul", id: 4 },
        { regno: "Mohit", id: 5 },
        { regno: "Kartik", id: 3 }
      ]
    };
  }
  function_as_props(list1) {
    let ninja = this.state.maps.concat({
      regno: list1,
      id: Math.random() * 10
    });
    this.setState({ maps: ninja });
  }
  function_as_props1(name) {
    let x = this.state.maps.filter(
      list => list.regno.toLocaleLowerCase() !== name.toLocaleLowerCase()
    );
    this.setState({
      maps: x
    });
  }
  render() {
    return (
      <React.Fragment>
        {this.state.maps.map(list => <div key={list.id}>{list.regno}</div>)}
        <FormsMap
          transpose={this.function_as_props.bind(this)}
          traverse={this.function_as_props1.bind(this)}
        />
      </React.Fragment>
    );
  }
}

export default App;

FormsMap.js

import React, { Component } from "react";

class FormsMap extends Component {
  state = {
    name: null,
    age: null,
    hobby: null
  };

  changes(e) {
    this.setState({
      [e.target.id]: e.target.value
    });
  }

  handle = e => {
    e.preventDefault();
    this.props.transpose(this.state.name);
  };

  dels = e => {
    this.setState({
      [e.target.id]: e.target.value
    });
  };

  del_button(e) {
    e.preventDefault();
    this.props.traverse(this.state.name);
  }
  render() {
    return (
      <React.Fragment>
        <form onSubmit={this.handle}>
          {" "}
          {/* After entering all info, Press Enter*/}
          <label htmlFor="labels"> Name : </label>
          <input
            type="text"
            id="name"
            placeholder="Your name goes here..."
            onChange={this.changes.bind(this)}
          />
          <label htmlFor="labels"> Age : </label>
          <input
            type="text"
            id="age"
            placeholder="Your age goes here..."
            onChange={this.changes.bind(this)}
          />
          <label htmlFor="labels"> Hobby : </label>
          <input
            type="text"
            id="hobby"
            placeholder="Your hobby goes here..."
            onChange={this.changes.bind(this)}
          />{" "}
          <br />
          <br />
          <input type="submit" value="SUBMIT" />
          <br />
          <br />
        </form>
        <input
          type="text"
          id="name"
          placeholder="Enter name to delete..."
          onChange={this.dels}
        />{" "}
        <button onClick={this.del_button.bind(this)}> DELETE </button>
      </React.Fragment>
    );
  }
}

export default FormsMap;

这是演示：https://codesandbox.io/s/xl97xm6zpo

通过仅传递一次道具多次执行状态和数组操作

1 个答案: