Reactjs 如何模拟使用React酶更改儿童的值

考虑到以下简单组件：

function ValueInput (props) {
  const [val, setVal] = useState(props.value);

  return <input value={val} onChange={v => setVal(v)}/>;
}

function MyComponent (props) {
  const [val, setVal] = useState(props.value);

  return (
    <div>
      <div>{val}</div>
      <ValueInput value={val}/>
    </div>
  );
}

即使强制更新也不会更改值。打印的组件保持不变：

  <MyComponent value={42}>
    <div>
      <div>
        42
      </div>
      <ValueInput value={42}>
        <input value={42} onChange={[Function: onChange]} />
      </ValueInput>
    </div>
  </MyComponent>

42

在您的代码中

function ValueInput (props) {
  const [val, setVal] = useState(props.value);

  return <input value={val} onChange={v => setVal(v)}/>;
}

另外，看看代码，不必复制子组件内的状态，您可以直接使用父组件的方法来操作和存储输入值：

function ValueInput ({val, setVal}) {
   return <input value={val} onChange={setVal}/>;
}

function MyComponent (props) {
  const [val, setVal] = useState(props.value);

 const handleChange = e => {
    const {value} = e.target;
    setVal(value);
  }

  return (
    <div>
      <div>{val}</div>
      <ValueInput value={val} setVal={handleChange}/>
    </div>
  );
}

函数值输入（{val，setVal}）{
回来
}
功能MyComponent（道具）{
const[val，setVal]=useState（props.value）；
常量handleChange=e=>{
const{value}=e.target；
setVal（值）；
}
返回(
{val}
);
}

function ValueInput (props) {
  const [val, setVal] = useState(props.value);

  return <input value={val} onChange={v => setVal(v)}/>;
}

function ValueInput (props) {
  const [val, setVal] = useState(props.value);

  const handleChange = e => {
    const {value} = e.target;
    setVal(value);
    props.setParentVal(value) // Pass the changed value to the parent
  }

  return <input value={val} onChange={handleChange}/>;
}

function MyComponent (props) {
  const [val, setVal] = useState(props.value);

  return (
    <div>
      <div>{val}</div>
      <ValueInput value={val} setParentVal={setVal}/>
    </div>
  );
}

function ValueInput ({val, setVal}) {
   return <input value={val} onChange={setVal}/>;
}

function MyComponent (props) {
  const [val, setVal] = useState(props.value);

 const handleChange = e => {
    const {value} = e.target;
    setVal(value);
  }

  return (
    <div>
      <div>{val}</div>
      <ValueInput value={val} setVal={handleChange}/>
    </div>
  );
}