If you want to trigger a re-render after the ref changes, you must use useState instead of useRef. Only that way can you ensure that the component will re-render. E.g.: function Component() { const [ref, setRef] = useState(); return <div ref={newRef => setRef(newRef)} /> } As described under useRef documentation: Keep in mind that useRef … Read more
I can’t answer the “should you” part of whether to use refs for this instead other than if you do, you don’t need those id values unless you use them for something else. But here’s how you would: Use useRef(null) to create the ref. const activeSlideRef = useRef(null); Put it on the Slide that’s currently … Read more
In C#, when you see something referring to a reference type (that is, a type declared with class instead of struct), then you’re essentially always dealing with the object through a pointer. In C++, everything is a value type by default, whereas in C# everything is a reference type by default. When you say “ref” … Read more
You require to extract the ref type elsewhere: interface RefObject { SayHi: () => void } then just refer to it in both places const Child = forwardRef((props: {name: string}, ref: Ref<RefObject>)=> { const {name} = props; useImperativeHandle(ref, () => ({ SayHi })); function SayHi() { console.log(“Hello ” + name); } return <div>{name}</div>; }); const … Read more
String refs are deprecated and material-ui does not support using them. I recommend reading: https://reactjs.org/docs/refs-and-the-dom.html Also to get a ref to the <input /> element you should use the inputRef prop. Read about it here. If your React is up to date you should use createRef or the useRef hook. Below are some examples // … Read more
So the thing about refs is that they aren’t guaranteed to be set on first render. You can be sure they are set during and after componentDidMount so you have two ways going forward. You could use the callback style ref and set state based on that. E.g. instead of passing your ref as the … Read more
The forwardRef api, (coupled with the useImperativeHandle hook) lets you customize how and where your refs are placed inside your custom components. Also, forwardRef is the only way to pass a ref to your custom function components. First, it’s important to understand that refs work differently on class components, function components, and regular DOM elements. … Read more
C# iterators are state machines internally. Every time you yield return something, the place where you left off should be saved along with the state of local variables so that you could get back and continue from there. To hold this state, C# compiler creates a class to hold local variables and the place it … Read more
The reason you cannot pass null is because a ref parameter is given special treatment by the C# compiler. Any ref parameter must be a reference that can be passed to the function you are calling. Since you want to pass null the compiler is refusing to allow this since you are not providing a … Read more
Because you forgot to assign the ref to some dom element. You are only creating it. Write it like this: class App extends React.PureComponent { constructor(props) { super(props); this.test = React.createRef(); } handleClick = () => alert(this.test.current.value) render() { return ( <div className=”App”> <input ref={this.test} /> <button onClick={this.handleClick}>Get Value</button> </div> ) } } Working Example.