For child-parent communication you should pass a function setting the state from parent to child, like this
class Parent extends React.Component {
constructor(props) {
super(props)
this.handler = this.handler.bind(this)
}
handler() {
this.setState({
someVar: 'some value'
})
}
render() {
return <Child handler = {this.handler} />
}
}
class Child extends React.Component {
render() {
return <Button onClick = {this.props.handler}/ >
}
}
This way the child can update the parent's state with the call of a function passed with props.
But you will have to rethink your components' structure, because as I understand components 5 and 3 are not related.
One possible solution is to wrap them in a higher level component which will contain the state of both component 1 and 3. This component will set the lower level state through props.
Answer from Ivan on Stack OverflowFor child-parent communication you should pass a function setting the state from parent to child, like this
class Parent extends React.Component {
constructor(props) {
super(props)
this.handler = this.handler.bind(this)
}
handler() {
this.setState({
someVar: 'some value'
})
}
render() {
return <Child handler = {this.handler} />
}
}
class Child extends React.Component {
render() {
return <Button onClick = {this.props.handler}/ >
}
}
This way the child can update the parent's state with the call of a function passed with props.
But you will have to rethink your components' structure, because as I understand components 5 and 3 are not related.
One possible solution is to wrap them in a higher level component which will contain the state of both component 1 and 3. This component will set the lower level state through props.
This is how to do it with the new useState hook.
Method - Pass the state changer function as a props to the child component and do whatever you want to do with the function:
import React, {useState} from 'react';
const ParentComponent = () => {
const[state, setState]=useState('');
return(
<ChildComponent stateChanger={setState} />
)
}
const ChildComponent = ({stateChanger, ...rest}) => {
return(
<button onClick={() => stateChanger('New data')}></button>
)
}
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Hello folks,
how can i change the state of a parent component inside a child component?
import React, { useState } from "react";
import Login from './components/Login/Login.js'; import './App.css';
function App() {
const [loginStatus, setloginStatus] = useState(false);
return (
<div className="App">
<Login />
</div>
);
}
export default App;
Specifically i am trying to do some login functionality. Based on the loginStatus i want to render the Login-Component. Inside the Login-Component i want to set loginStatus = true, when user/pw is correct. Can i maybe pass the setloginStatus to the Login-Component, or something?
Are there any keywords i can look for in the React documentation?
The state should be managed in the parent component. You can transfer the open value to the child component by adding a property.
class ParentComponent extends Component {
constructor(props) {
super(props);
this.state = {
open: false
};
this.toggleChildMenu = this.toggleChildMenu.bind(this);
}
toggleChildMenu() {
this.setState(state => ({
open: !state.open
}));
}
render() {
return (
<div>
<button onClick={this.toggleChildMenu}>
Toggle Menu from Parent
</button>
<ChildComponent open={this.state.open} />
</div>
);
}
}
class ChildComponent extends Component {
render() {
return (
<Drawer open={this.props.open}/>
);
}
}
The parent component can manage child state passing a prop to child and the child convert this prop in state using componentWillReceiveProps.
class ParentComponent extends Component {
state = { drawerOpen: false }
toggleChildMenu = () => {
this.setState({ drawerOpen: !this.state.drawerOpen })
}
render() {
return (
<div>
<button onClick={this.toggleChildMenu}>Toggle Menu from Parent</button>
<ChildComponent drawerOpen={this.state.drawerOpen} />
</div>
)
}
}
class ChildComponent extends Component {
constructor(props) {
super(props)
this.state = {
open: false
}
}
componentWillReceiveProps(props) {
this.setState({ open: props.drawerOpen })
}
toggleMenu() {
this.setState({
open: !this.state.open
})
}
render() {
return <Drawer open={this.state.open} />
}
}