[英]React JS : grandparent component's setState method doesn't update state of a grandchild input field onChange event click
In the same code, I was able to the get the grandparent component's setState
method to update accordingly for an onClick
event from the grandchild component, however, for the onChange
event, it is failing.在相同的代码中,我能够获取祖父组件的setState
方法,以便相应地更新来自孙组件的onClick
事件,但是,对于onChange
事件,它失败了。 I am not getting any errors.我没有收到任何错误。
class GrandChild extends React.Component {
constructor(props) {
super(props);
this.handleChange = this.handleChange.bind(this);
}
changeNumber=()=> {
this.props.changeNumber();//call child method
}
handleChange(e) {
this.props.onChange(e.target.value);
}
render() {
const data = this.props.data;
return(
<div>
<h1>The number is {this.props.number}</h1>
<input type="text" value = {data} onChange={this.handleChange} />
<button onClick={this.changeNumber}>Increase number by 1</button>
</div>
)
}
}
class Child extends React.Component {
render() {
return(
<div>
<GrandChild number={this.props.number} changeNumber={this.props.changeNumber} value={this.props.data} onChange={this.props.handleChange}/>
</div>
)
}
}
class App extends React.Component {
constructor() {
super()
this.state = {
number: 1,
data: ""
}
this.handleChange = this.handleChange.bind(this);
}
handleChange(data) {
this.setState({data:this.state.data});
console.log(data);
}
changeNumber=()=>{
this.setState((prevState)=>{
console.log(prevState,this.state.data);
return {
number : prevState.number + 1
}
});
}
render() {
const data = this.state.data;
const input = data;
return (
<Child number={this.state.number}
changeNumber = {this.changeNumber}
data={input}
onChange = {this.handleChange}
/>
);
}
}
ReactDOM.render(<App />, document.getElementById('root'));
Console Result: Object { data: "", number: 1 } ""控制台结果:对象{数据:“”,数量:1}“”
result screenshot: console.log result结果截图: console.log 结果
see code pen for live code: https://codepen.io/codehorse/pen/yLyEwBw?editors=0011实时代码见代码笔: https : //codepen.io/codehorse/pen/yLyEwBw?editors=0011
Your improved code with live demo https://codesandbox.io/s/laughing-sky-kk97b您使用现场演示改进的代码https://codesandbox.io/s/laughing-sky-kk97b
What need to change <GrandChild number={this.props.number} changeNumber={this.props.changeNumber} value={this.props.data} onChange={this.props.onChange}/>
什么需要改变<GrandChild number={this.props.number} changeNumber={this.props.changeNumber} value={this.props.data} onChange={this.props.onChange}/>
Complete Code完整代码
class GrandChild extends React.Component {
constructor(props) {
super(props);
this.handleChange = this.handleChange.bind(this);
}
changeNumber = () => {
this.props.changeNumber(); //call child method
};
handleChange(e) {
this.props.onChange(e.target.value);
}
render() {
const data = this.props.data;
return (
<div>
<h1>The number is {this.props.number}</h1>
<input type="text" value={data} onChange={this.props.onChange} />
<button onClick={this.changeNumber}>Increase number by 1</button>
</div>
);
}
}
class Child extends React.Component {
render() {
return (
<div>
<GrandChild
number={this.props.number}
changeNumber={this.props.changeNumber}
value={this.props.data}
onChange={this.props.onChange}
/>
</div>
);
}
}
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
number: 1,
data: ""
};
}
handleChange = e => {
this.setState({ data: e.target.value });
console.log(e.target.value);
};
changeNumber = () => {
this.setState(prevState => {
console.log(prevState, this.state.data);
return {
number: prevState.number + 1
};
});
};
render() {
const data = this.state.data;
const input = data;
return (
<Child
number={this.state.number}
changeNumber={this.changeNumber}
data={input}
onChange={this.handleChange}
/>
);
}
}
export default App;
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