无法使用具有onchange的material-ui自动完成功能中的选择项来获取event.target.value

***来自建议的代码更新****** 我正在学习使用material-ui。我找不到将其与事件处理相结合的许多示例。我使用了自动完成功能和文本字段来创建建议的从API提取的数据列表。我可以呈现选定的列表,但是单击选择之一后,我无法获得单击的值传递给react类的成员函数。我需要将事件正确绑定到自动完成功能吗?我应该怎么做。我的代码中的第25行将事件目标记录到控制台,但始终为0(我假设为null)。如何将this.state.data的值设置为clicked选项?

我尝试添加autoSelect = {true}

我还尝试将这行代码移到textarea中。
onChange = {this.updateState}

import React from "react"
import TextField from '@material-ui/core/TextField';
import Autocomplete from '@material-ui/lab/Autocomplete';

class App extends React.Component {


    constructor(props) {
        super(props);

        this.state = {
            data: null,isLoaded: false,itemSelected: false,inputVal: ''}

            this.updateState = this.updateState.bind(this)

        };

        updateState(e) {
            e.persist()
            const newValue = e.target.value
            this.setState({inputVal: newValue,itemSelected: true});
            console.log(e.target.value);

            // eventually I want to render a DIV with data from the selected value
        }

        /// fetch some data

    componentDidmount() {
        fetch('http://jsonplaceholder.typicode.com/posts')
            .then(response => response.json())
            /* .then(json => console.log(json)) */

            .then(data => this.setState({data,isLoaded: true}));
    }

    render() {

        const {isLoaded,itemSelected} = this.state;




        if (!isLoaded) {
            return <div> loading ...</div>;
        } else if (itemSelected) {
            return <div> item selected </div>
        } else {
            const limo = this.state.data;
            return (
                <div>

                    <Autocomplete
                        freeSolo
                        disableclearable
                        autoSelect={true}
                        id = "limoSelect"
                        onChange={this.updateState}
                        value = {this.state.inputVal}
                        options={limo.map(option => "body: '" + option.body + '\n' + "'      id: " + option.id)}
                        renderInput={params => (

                            <TextField
                                {...params}
                                label="Type In Content"
                                id="limoText"
                                value = ''
                                autoSelect={true}
                                margin="normal"
                                variant="outlined"
                                fullWidth
                                InputProps={{...params.InputProps,type: 'search'}}

                            />


                        )}
                    />
                </div>
            );

        }
    }
}

App.defaultProps = {}

export default App;

控制台记录为零。 当您单击选项时,将调用updateState并设置此变量 this.state.itemSelected = true; 没有错误信息。 我希望可以通过updateState中的console.log来记录单击的项目!

a932182372 回答:无法使用具有onchange的material-ui自动完成功能中的选择项来获取event.target.value

onChange签名:函数(事件:对象,值:任意)=>无效

这是一个例子:

import React from 'react';
import Chip from '@material-ui/core/Chip';
import Autocomplete from '@material-ui/lab/Autocomplete';
import TextField from '@material-ui/core/TextField';

export default class Tags extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      tags: []
    };
    this.onTagsChange = this.onTagsChange.bind(this);
  }

  onTagsChange = (event,values) => {
    this.setState({
      tags: values
    },() => {
      // This will output an array of objects
      // given by Autocompelte options property.
      console.log(this.state.tags);
    });
  }

  render() {
    return (
      <div style={{ width: 500 }}>
        <Autocomplete
          multiple
          options={top100Films}
          getOptionLabel={option => option.title}
          defaultValue={[top100Films[13]]}
          onChange={this.onTagsChange}
          renderInput={params => (
            <TextField
              {...params}
              variant="standard"
              label="Multiple values"
              placeholder="Favorites"
              margin="normal"
              fullWidth
            />
          )}
        />
      </div>
    );
  }
}

const top100Films = [
  { title: 'The Shawshank Redemption',year: 1994 },{ title: 'The Godfather',year: 1972 },{ title: 'The Godfather: Part II',year: 1974 },{ title: 'The Dark Knight',year: 2008 },{ title: '12 Angry Men',year: 1957 },{ title: "Schindler's List",year: 1993 },{ title: 'Pulp Fiction',{ title: 'The Lord of the Rings: The Return of the King',year: 2003 },{ title: 'The Good,the Bad and the Ugly',year: 1966 },{ title: 'Fight Club',year: 1999 },{ title: 'The Lord of the Rings: The Fellowship of the Ring',year: 2001 },{ title: 'Star Wars: Episode V - The Empire Strikes Back',year: 1980 },{ title: 'Forrest Gump',{ title: 'Inception',year: 2010 },];
,

编辑:使用e.target.textContent可以解决问题。
这是一个实时Codesandbox,用于检查代码(修改了某些部分,应用了下面的技巧以及其他一些东西)。


不要像这样手动更改状态:

this.state.itemSelected = true

使用setState(就像您已经在处理其他状态项一样)

 updateState(e) {
    this.setState({ inputVal: e.target.value,itemSelected: true });
    console.log(e.target.value);
    // eventually I want to render a DIV with data from the selected value
  }

还有一个技巧,您可以使用数组解构:

const {isLoaded,itemSelected} = this.state;

代替

var isloaded = this.state.isLoaded;
var itemSelected = this.state.itemSelected;
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