react hooks useRef 怎么负值
时间: 2023-07-21 08:05:13 浏览: 59
要给 useRef 赋值,可以使用 `current` 属性来访问或更改引用的当前值。例如:
```
import React, { useRef } from 'react';
function Example() {
const inputRef = useRef(null);
const handleClick = () => {
inputRef.current.value = 'New Value';
};
return (
<div>
<input type="text" ref={inputRef} />
<button onClick={handleClick}>Change Value</button>
</div>
);
}
```
在上面的例子中,我们使用了 useRef 创建一个名为 inputRef 的引用,并将其分配给 input 元素的 ref 属性。然后,当用户单击按钮时,我们使用 `inputRef.current` 来访问 input 元素的当前值,并将其更改为 'New Value'。
相关问题
react hooks useRef
React hooks useRef is a tool designed to create a reference to a specific element or value within a React component. It is commonly used to access the DOM elements that are rendered in a React application. Do you have any specific questions or concerns regarding useRef?
reacthook useRef
React Hook `useRef` is a function that returns a mutable object with a `current` property that can be used to store and access a value across renders. It is similar to creating an instance property on a class component.
The `useRef` hook is used to:
1. Store a value that persists across renders without triggering a re-render.
2. Access the properties of a DOM node or a React component instance.
The most common use case of `useRef` is to access the DOM nodes, such as:
1. Focus an input element
2. Scroll a container
3. Measure the size of an element
Example:
```
import React, { useRef } from 'react';
function Example() {
const inputRef = useRef(null);
const handleClick = () => {
inputRef.current.focus();
};
return (
<div>
<input type="text" ref={inputRef} />
<button onClick={handleClick}>Focus Input</button>
</div>
);
}
```
In the above example, we are using `useRef` to store a reference to the input element, and in the `handleClick` function, we are accessing that reference to call the `focus` method on the input element.
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