Select 在 Form.Item 内带有 value 属性不会反映该 value 属性的任何变化

Question

I'm having trouble with antd forms in regard to Select input. I have two Select inputs and I need the second input to "reset" to the first option when the first input changes value.

I need to keep track of each Select value with React.useState because —in my real code— those values are used to make a request to a backend and re-populate other Select inputs but the first one, and each Select have a different amount of options, thus is desirable that they get "reset" to the first option.

How can I achieve what I'm looking for?

Answer 1

Since you decide to control the input field with value and onChange ,

You don't need the Form name , remove it.

Then set the first hander, check if the value changed to decide whether set the second to default or not.

import React from "react";
import ReactDOM from "react-dom";
import { Select, Form } from "antd";
import "antd/dist/antd.css";

const fieldA = [{ value: 1, text: "Hello" }, { value: 2, text: "World" }];
const fieldB = [{ value: 1, text: "A" }, { value: 2, text: "B" }];

const App = () => {
  const [valueA, setValueA] = React.useState(null);
  const [valueB, setValueB] = React.useState(null);
  const setFieldA = (value: number) => {
    if (valueA !== value) {
      setValueB(null);
    }
    setValueA(value);
  };

  const setFieldB = (value: number) => {
    setValueB(value);
  };

  return (
    <Form layout="vertical">
      <Form.Item label="Field A">
        <Select value={valueA} onChange={setFieldA}>
          {fieldA.map(field => (
            <Select.Option value={field.value}>{field.text}</Select.Option>
          ))}
        </Select>
      </Form.Item>
      <Form.Item label="Field B">
        <Select value={valueB} onChange={setFieldB}>
          {fieldB.map(field => (
            <Select.Option value={field.value}>{field.text}</Select.Option>
          ))}
        </Select>
      </Form.Item>
      <div>
        Field A "real" value: {valueA}
        <br />
        Field B "real" value: {valueB}
      </div>
    </Form>
  );
};

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

Answer 2

If you add Select into the Form and Form.Item and set a name for Form.Item , the Select is completely controlled by the Form . You need to use the Form's api to control the Select or simply remove the name

import React from "react";
import ReactDOM from "react-dom";
import { Select, Form } from "antd";
import "antd/dist/antd.css";

const fieldA = [{ value: 1, text: "Hello" }, { value: 2, text: "World" }];
const fieldB = [{ value: 1, text: "A" }, { value: 2, text: "B" }];

const App = () => {
  const [myvalues, setMyvalues] = React.useState({ valueA: 1, valueB: 1 });
  const setFieldA = (value: number) => {
    setMyvalues({ valueA: value, valueB: 1 });
    form.setFieldsValue({ valueA: value, valueB: 1 });
  };
  const setFieldB = (value: number) => {
    setMyvalues({ ...myvalues, valueB: value });
    form.setFieldsValue({ ...myvalues, valueB: value });
  };
  const [form] = Form.useForm();
  return (
    <Form layout="vertical" form={form} initialValues={myvalues}>
      <Form.Item name="valueA" label="Field A" shouldUpdate>
        <Select value={myvalues.valueA} onChange={setFieldA}>
          {fieldA.map(field => (
            <Select.Option value={field.value}>{field.text}</Select.Option>
          ))}
        </Select>
      </Form.Item>
      <Form.Item name="valueB" label="Field B" shouldUpdate>
        <Select value={myvalues.valueB} onChange={setFieldB}>
          {fieldB.map(field => (
            <Select.Option value={field.value}>{field.text}</Select.Option>
          ))}
        </Select>
      </Form.Item>
      <div>
        Field A "real" value: {myvalues.valueA}.<br />
        Field B "real" value: {myvalues.valueB}
      </div>
    </Form>
  );
};

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

You can check hereCodeSandBox . Hope it helps