Why does the form not receive select data in AntD?

Question

I am using AntD select. When I put select into a separate component, the form does not see the value Tell me why the form does not receive data on submit?

Example

const SelectCust = () => {
return (
  <Select
    mode="multiple"
    placeholder="Please select favourite colors"
    style={{ width: 500 }}
    name="select-multiple"
  >
    <Option value="red">Red</Option>
    <Option value="green">Green</Option>
    <Option value="blue">Blue</Option>
  </Select>
  )};

const Demo = () => {
  const onFinish = values => {
    console.log("Received values of form: ", values); // {custom:undefined}
  };

return (
  <Form name="validate_other" onFinish={onFinish}>
    <Form.Item name="custom" label="Select custom">
      <SelectCust />
    </Form.Item>

    <Form.Item>
      <Button type="primary" htmlType="submit">
        Submit
      </Button>
  </Form.Item>
</Form>
)};

Answer 1

If you wrap <Select> with <Form.Item> it works correctly:

const SelectCust = () => {
  return (
    <Form.Item name="custom" label="Select custom">
      <Select
        mode="multiple"
        placeholder="Please select favourite colors"
        style={{ width: 500 }}
        name="select-multiple"
      >
        <Option value="red">Red</Option>
        <Option value="green">Green</Option>
        <Option value="blue">Blue</Option>
      </Select>
    </Form.Item>
  );
};

Here is updated Demo component:

const Demo = () => {
  const onFinish = values => {
    console.log("Received values of form: ", values);
  };

  return (
    <Form name="validate_other" onFinish={onFinish}>
      <SelectCust />

      <Form.Item
        wrapperCol={{
          span: 12,
          offset: 6
        }}
      >
        <Button type="primary" htmlType="submit">
          Submit
        </Button>
      </Form.Item>
    </Form>
  );
};

---

EDIT 1

It seemed wrong to me that wrapping <Select> with <Form.Item> solved the problem, so I looked up <Form> documentation .

Here is updated code:

const SelectCust = props => {
  return (
    <Select
      mode="multiple"
      placeholder="Please select favourite colors"
      onChange={props.onColorChange}
    >
      <Option value="red">Red</Option>
      <Option value="green">Green</Option>
      <Option value="blue">Blue</Option>
    </Select>
  );
};

const Demo = () => {
  const [form] = Form.useForm();

  const onFinish = values => console.log(values);

  const handleColorChanged = value => {
    form.setFieldsValue({ custom: value });
  };

  return (
    <Form name="validate_other" form={form} onFinish={onFinish}>
      <Form.Item name="custom" label="Select custom">
        <SelectCust onColorChange={handleColorChanged} />
      </Form.Item>

      <Form.Item
        wrapperCol={{
          span: 12,
          offset: 6
        }}
      >
        <Button type="primary" htmlType="submit">
          Submit
        </Button>
      </Form.Item>
    </Form>
  );
};

Update has 3 important steps:

1. Add const [form] = Form.useForm() in the beginning of Demo component
2. Implement handleColorChanged function and pass it as props to SelectCust . Handler sets form value by calling form.setFieldsValue() .
3. Pass from as props to <Form> component