useRef
/*
A common use case is to access a child imperatively:
*/
function TextInputWithFocusButton() {
const inputEl = useRef(null);
const onButtonClick = () => {
// `current` points to the mounted text input element
inputEl.current.focus();
};
return (
<>
<input ref={inputEl} type="text" />
<button onClick={onButtonClick}>Focus the input</button>
</>
);
}refs react js
class Lesson9Refs extends Component {
onAddProduct = () => {
alert(this.refs.productname.value);
}
return (
<div>
<div className="container">
<div class="card mt-10">
<div class="card-header">
Featured
</div>
<div class="card-body">
<label> Product Name: </label>
<input type='text' className="form-control" ref="productname" />
<button type="submit" className="btn btn-primary" onClick={ this.onAddProduct } >
Add Product
</button>
</div>
</div>
<div className="row mt-10">
{ elements }
</div>
</div>
</div>
);
}
}
export default Lesson9Refs;when to use react ref
WHEN TO USE REACT'S REF ATTRIBUTE?
But it is not always a good idea to use the ref attribute. The general rule of thumb is to avoid it. The official React documentation mentions three occasions where you can use it because you have no other choice.
Managing focus, text selection, or media playback.
Integrating with third-party DOM libraries.
Triggering imperative animations.use ref in component reactjs
class CustomTextInput extends React.Component {
constructor(props) {
super(props);
this.textInput = null;
this.setTextInputRef = element => { this.textInput = element; };
this.focusTextInput = () => { // Donne le focus au champ texte en utilisant l’API DOM native. if (this.textInput) this.textInput.focus(); }; }
componentDidMount() {
// Focus automatique sur le champ au montage
this.focusTextInput(); }
render() {
// Utilise la fonction de rappel `ref` pour stocker une référence à l’élément
// DOM du champ texte dans une propriété d’instance (ex. this.textInput)
return (
<div>
<input
type="text"
ref={this.setTextInputRef} />
<input
type="button"
value="Donner le focus au champ texte"
onClick={this.focusTextInput} />
</div>
);
}
}Copyright © 2021 Codeinu
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