将变量从子组件传递到父组件

import React, { useState } from 'react';
import ChildComponent from './ChildComponent';

function ParentComponent() {
  const [variable, setVariable] = useState('');

  const handleVariableChange = (value) => {
    setVariable(value);
  };

  return (
    <div>
      <ChildComponent onVariableChange={handleVariableChange} />
      <p>Variable from child component: {variable}</p>
    </div>
  );
}

export default ParentComponent;

import React, { useState } from 'react';

function ChildComponent({ onVariableChange }) {
  const [inputValue, setInputValue] = useState('');

  const handleInputChange = (event) => {
    setInputValue(event.target.value);
    onVariableChange(event.target.value);
  };

  return (
    <div>
      <input type="text" value={inputValue} onChange={handleInputChange} />
    </div>
  );
}

export default ChildComponent;