2

我正在尝试使用React Select在 ReactJS 中设置我的 brandSelect 道具的状态，但是我对如何做到这一点感到困惑？

这是我当前的代码：

class VehicleSelect extends React.Component {

  constructor(props) {
    super(props);

    this.state = { brandSelect: ""};

  }
  render() {
    var options = [
    { value: 'Volkswagen', label: 'Volkswagen' },
    { value: 'Seat', label: 'Seat' }
    ];


    return (
      <Select
          name="form-field-name"
          value={this.state.brandSelect}
          options={options}
          placeholder="Select a brand"
          searchable={false}
          onChange={}
      />
    )
  }
};

选择该选项后，我希望将状态设置为所选选项。

有谁知道 React Select 是如何做到的，因为文档并没有真正涵盖这一点？到目前为止，我已经尝试制作一个附加到 onChange 道具的设置状态的函数，但这不起作用。

4

5 回答 5

3

在 react 16.8+ 中，使用 React hooks 的实现应该是这样的：

Hooks是 React 16.8 中的新增功能

function VehicleSelect() {

  const options = [
    { value: 'volkswagen', label: 'Volkswagen' },
    { value: 'seat', label: 'Seat' }
  ];

  const [selectedOption, setSelectedOption] = useState({ value: 'volkswagen', label: 'Volkswagen' });

  const [handleChange] = useState(() => {
    return () => {
      setSelectedOption(selectedOption);
    };
  });

  return (
    <div className="App">
      <Select
        name="form-field-name"
        placeholder="Select a brand"
        searchable={false}
        value={selectedOption}
        onChange={handleChange}
        options={options}
      />
    </div>
  );
}
于 2020-01-02T19:27:37.763 回答
0

我在我的代码中使用它来使用 Selector：

class VehicleSelect extends React.Component {

  constructor(props) {
    super(props);

    this.state = { brandSelect: ""};

  }

  onChange(event) {
    this.setState({brandSelect: event.target.value}); // important
  }

  render() {
    var options = [
    { value: 'Volkswagen', label: 'Volkswagen' },
    { value: 'Seat', label: 'Seat' }
    ];


    return (
      <Select
          name="form-field-name"
          value={this.state.brandSelect}
          options={options}
          placeholder="Select a brand"
          searchable={false}
          onChange={this.onChange.bind(this)}
      />
    )
  }
};
于 2019-12-01T10:28:42.780 回答
0

尝试这个：

class VehicleSelect extends React.Component {

    constructor(props) {
      super(props);

      this.state = {
        brandSelect: ""
      };

    }
    onSelectChanged(value) {
      this.setState({
        brandSelect: value
      });
    }
    render() {
        var options = [{
          value: 'Volkswagen',
          label: 'Volkswagen'
        }, {
          value: 'Seat',
          label: 'Seat'
        }];

        <Select
       name="form-field-name"
       value={this.state.brandSelect}
       options={options}
       placeholder="Select a brand"
       searchable={false}
       onChange={this.onSelectChanged.bind(this)}
       />

您需要一个onChange事件处理程序。将参数传递给事件处理函数，在这种情况下将是Select输入的选定值，然后使用选定值设置状态。brandSelect

于 2016-07-25T16:25:30.033 回答
0 
const Layout = (props: any) => {

//Row First
const [rows, setRow] = useState({
    rowFirst: "",
    columnFirst: "",
    columnSecond: 0
});

const handleChangeRowFirst = (e: { target: { name: any; value: any; }; }) => {


    setRow({ ...rows, [e.target.name]: e.target.value });

    console.log("row", rows);

    props.dispatch({
        type: "setRow",
        payload: rows
    });

};

const onSubmitForm = (e: any) => {
    e.preventDefault();
    if (!rows.rowFirst) {
        alert("rowFirst is empty.")
    }
    else if (!rows.columnFirst) {
        alert("columnFirst or rowFirst is empty.")
    }
    else if (!rows.columnSecond) {
        alert("columnSecond is empty.")
    }
}



return (
    <>
        <Grid container className="containerMatrix">
            <form onSubmit={onSubmitForm} className="formMatrix">
                <Grid item xs={6} md={5}>
                    <Box id="test" className="martixNum">
                        <Typography variant="h5" gutterBottom className="nameColMatrix">
                            Enter Numbers First Matrix
                        </Typography>

                        <Box className="martixFirst">
                            <TextField
                                type="number"
                                InputProps={{
                                    inputProps: {
                                        max: 99, min: 0
                                    }
                                }}
                                label="Row" onChange={handleChangeRowFirst} name="rowFirst" id="num1" value={rows.rowFirst}
                            />
                            <TextField
                                type="number"
                                InputProps={{
                                    inputProps: {
                                        max: 99, min: 0
                                    }
                                }}
                                label="Column" onChange={handleChangeRowFirst} name="columnFirst" id="num2" value={rows.columnFirst}
                            />
                        </Box>
                    </Box>
                </Grid>

                <Grid item xs={6} md={5}>
                    <Box id="test" className="martixNum">
                        <Typography variant="h5" gutterBottom className="nameColMatrix">
                            Enter Numbers Second Matrix
                        </Typography>
                        <Box className="martixFirst">
                            <TextField
                                type="number"
                                InputProps={{
                                    inputProps: {
                                        max: 99, min: 0
                                    }
                                }}
                                label="Row" onChange={handleChangeRowFirst} name="columnFirst" id="num3" value={rows.columnFirst}
                            />

                            <TextField
                                type="number"
                                InputProps={{
                                    inputProps: {
                                        max: 99, min: 0
                                    }
                                }}
                                label="Column" onChange={handleChangeRowFirst} name="columnSecond" id="num4"
                            />
                        </Box>

                    </Box>
                </Grid>
                <Grid item xs={6} md={5}>
                    <Box>
                        <Button variant="contained" color="primary" type="submit">
                            Primary
                        </Button>
                    </Box>
                </Grid>
            </form>
        </Grid>
    </>
)
}
于 2021-09-02T21:45:20.887 回答
0

您可以尝试_onChange向您的组件添加处理程序，它将处理表单<Select />组件的更改。

class VehicleSelect extends React.Component {

  constructor(props) {
    super(props);

    this.state = { brandSelect: ""};

  }

  _onChange(value) {
    //console.log(value) - just to see what we recive from <Select />
    this.setState({brandSelect: value});
  }

  render() {
    var options = [
    { value: 'Volkswagen', label: 'Volkswagen' },
    { value: 'Seat', label: 'Seat' }
    ];


    return (
      <Select
          name="form-field-name"
          value={this.state.brandSelect}
          options={options}
          placeholder="Select a brand"
          searchable={false}
          onChange={this._onChange.bind(this)}
      />
    )
  }
};
于 2016-07-25T16:24:30.867 回答