te')); return $arr; } /* 遍历用户所有主题 * @param $uid 用户ID * @param int $page 页数 * @param int $pagesize 每页记录条数 * @param bool $desc 排序方式 TRUE降序 FALSE升序 * @param string $key 返回的数组用那一列的值作为 key * @param array $col 查询哪些列 */ function thread_tid_find_by_uid($uid, $page = 1, $pagesize = 1000, $desc = TRUE, $key = 'tid', $col = array()) { if (empty($uid)) return array(); $orderby = TRUE == $desc ? -1 : 1; $arr = thread_tid__find($cond = array('uid' => $uid), array('tid' => $orderby), $page, $pagesize, $key, $col); return $arr; } // 遍历栏目下tid 支持数组 $fid = array(1,2,3) function thread_tid_find_by_fid($fid, $page = 1, $pagesize = 1000, $desc = TRUE) { if (empty($fid)) return array(); $orderby = TRUE == $desc ? -1 : 1; $arr = thread_tid__find($cond = array('fid' => $fid), array('tid' => $orderby), $page, $pagesize, 'tid', array('tid', 'verify_date')); return $arr; } function thread_tid_delete($tid) { if (empty($tid)) return FALSE; $r = thread_tid__delete(array('tid' => $tid)); return $r; } function thread_tid_count() { $n = thread_tid__count(); return $n; } // 统计用户主题数 大数量下严谨使用非主键统计 function thread_uid_count($uid) { $n = thread_tid__count(array('uid' => $uid)); return $n; } // 统计栏目主题数 大数量下严谨使用非主键统计 function thread_fid_count($fid) { $n = thread_tid__count(array('fid' => $fid)); return $n; } ?>javascript - Passing value to state using react-select - Stack Overflow
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javascript - Passing value to state using react-select - Stack Overflow

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I'm new to react and trying to learn on my own. I started using react-select to create a dropdown on a form and now I'm trying to pass the value of the option selected. My state looks like this.

this.state = {
  part_id: "",
  failure: ""
};

Then in my render

const {
  part_id,
  failure
} = this.state;

My form looks has 2 fields

<FormGroup>
  <Label for="failure">Failure</Label>
  <Input
    type="text"
    name="failure"
    placeholder="Failure"
    value={failure}
    onChange={this.changeHandler}
    required
    />
  </FormGroup>
  <FormGroup>
  <Label for="part_id">Part</Label>
  <Select
    name="part_id"
    value={part_id}
    onChange={this.changeHandler}
    options={option}
  />
  </FormGroup>

the changeHandler looks like this

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

The change handler works fine for the input but the Select throws error saying cannot read property name. I went through the API docs and came up with something like this for the Select onChange

onChange={part_id => this.setState({ part_id })}

which sets the part_id as a label, value pair. Is there a way to get just the value? and also how would I implement the same with multiselect?

I'm new to react and trying to learn on my own. I started using react-select to create a dropdown on a form and now I'm trying to pass the value of the option selected. My state looks like this.

this.state = {
  part_id: "",
  failure: ""
};

Then in my render

const {
  part_id,
  failure
} = this.state;

My form looks has 2 fields

<FormGroup>
  <Label for="failure">Failure</Label>
  <Input
    type="text"
    name="failure"
    placeholder="Failure"
    value={failure}
    onChange={this.changeHandler}
    required
    />
  </FormGroup>
  <FormGroup>
  <Label for="part_id">Part</Label>
  <Select
    name="part_id"
    value={part_id}
    onChange={this.changeHandler}
    options={option}
  />
  </FormGroup>

the changeHandler looks like this

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

The change handler works fine for the input but the Select throws error saying cannot read property name. I went through the API docs and came up with something like this for the Select onChange

onChange={part_id => this.setState({ part_id })}

which sets the part_id as a label, value pair. Is there a way to get just the value? and also how would I implement the same with multiselect?

Share Improve this question edited Mar 19, 2020 at 15:10 keikai 15.2k9 gold badges55 silver badges72 bronze badges asked Mar 4, 2020 at 4:34 Justin SJustin S 2561 gold badge3 silver badges16 bronze badges
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3 Answers 3

Reset to default 10

The return of react-select onChange event and the value props both have the type as below

event / value:

null | {value: string, label: string} | Array<{value: string, label: string}>

So what the error means is that you can't find an attribute of null (not selected), or any attributes naming as name (you need value or label)

For multiple selections, it returns the sub-list of options.

You can find the related info in their document

const options = [
  { value: 'chocolate', label: 'Chocolate' },
  { value: 'strawberry', label: 'Strawberry' },
  { value: 'vanilla', label: 'Vanilla' },
];

Update

For your situation (single selection)

  • option having type as above
const option = [
  {value: '1', label: 'name1'},
  {value: '2', label: 'name2'}
]
  • state save selected value as id
changeHandler = e => {
  this.setState({ part_id: e ? e.value : '' });
};
  • pick selected option item via saved id
  <Select
    name="part_id"
    value={option.find(item => item.value === part_id)}
    onChange={this.changeHandler}
    options={option}
  />

For multiple selections

  • state save as id array
changeHandler = e => {
  this.setState({ part_id: e ? e.map(x => x.value) : [] });
};
  • pick via filter
  <Select
    isMulti // Add this props with value true
    name="part_id"
    value={option.filter(item => part_id.includes(item.value))}
    onChange={this.changeHandler}
    options={option}
  />

onChange function is a bit different in react-select

It passes array of selected values, you may get first one like

 onChange={([selected]) => {
    // React Select return object instead of value for selection
    // return { value: selected };
    setValue(selected)
 }}

I have tried the above solutions but some of these solutions does update the state but it doesn't gets rendered on the Select value instantly.

Herewith a demo example:

this.state = {
          part_id: null,
        };

handleUpdate = (part_id) => {
    this.setState({ part_id: part_id.value }, () =>
        console.log(`Option selected:`, this.state.part_id)
    );
};

const priceOptions = [
    { value: '999', label: 'Item One' },
    { value: '32.5', label: 'Item Two' },
    { value: '478', label: 'Item Three' }
]

<Select
    onChange={this.handleUpdate}
    value={priceOptions.find(item => item.value === part_id)}
    options={priceOptions}
    placeholder={<div>Select option</div>}
/>
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