forwardRef useImperativeHand
时间: 2023-11-11 14:14:54 浏览: 35
forwardRef is a React hook that allows you to get a reference to a child component from its parent. This is useful when you need to access the child component's imperative methods or properties.
The useImperativeHandle is a hook that can be used inside a child component to customize the instance value that is exposed to the parent when using forwardRef. In other words, it allows you to define which functions or properties of the child component can be accessed by the parent via the ref.
Here is an example of how to use forwardRef and useImperativeHandle:
In the parent component:
```jsx
import React, { useRef } from 'react';
import ChildComponent from './ChildComponent';
function ParentComponent() {
const childRef = useRef();
// Accessing the child component's imperative methods
const handleClick = () => {
childRef.current.someMethod();
};
return (
<div>
<ChildComponent ref={childRef} />
<button onClick={handleClick}>Call Child Method</button>
</div>
);
}
export default ParentComponent;
```
In the child component:
```jsx
import React, { forwardRef, useImperativeHandle } from 'react';
const ChildComponent = forwardRef((props, ref) => {
// Exposing imperative methods to the parent
useImperativeHandle(ref, () => ({
someMethod() {
console.log('This method is called from the parent');
}
}));
return <div>Child Component</div>;
});
export default ChildComponent;
```
In this example, the parent component uses forwardRef to get a reference to the ChildComponent. The child component uses useImperativeHandle to expose the `someMethod` to the parent through the ref. The parent can then call `someMethod` by accessing it through `childRef.current.someMethod()`.