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[英]How to send array of objects data from child component to parent component and store in the parent object using react hooks?
[英]How can i send multiple data as an object to parent component from child component in React?
從子組件我想在父組件中傳遞一些數據。 並且基於數據還想更新父組件的狀態。 我以下面的方式嘗試。 但是每次我更改輸入字段updatedHandler()都會被調用。 本應僅在單擊按鈕時調用。
父組件:
class Blog extends Component {
state = {
posts: [],
selectedPostId: null
};
componentDidMount() {
axios.get('https://jsonplaceholder.typicode.com/posts')
.then(response => {
const posts = response.data.slice(0, 3);
const updatedPosts = posts.map((post) => {
return {
...post,
author: 'Tanvir'
}
});
this.setState({ posts: updatedPosts })
});
}
selectedPostHandler = (id) => {
this.setState({ selectedPostId: id })
};
updatedPostsHandler = (post) => {
// axios.post('https://jsonplaceholder.typicode.com/posts/', post)
// .then(response => {
// }
// );
console.log(post);
}
render() {
const posts = this.state.posts.map(
post => <Post
key={post.id}
title={post.title}
author={post.author}
clicked={() => this.selectedPostHandler(post.id)} />
);
return (
<div>
<section className="Posts">
{posts}
</section>
<section>
<FullPost id={this.state.selectedPostId} />
</section>
<section>
<NewPost
newPostCreated={this.updatedPostsHandler} />
</section>
</div>
);
}
}
子組件:
class NewPost extends Component {
state = {
title: '',
content: '',
author: 'Max',
post: ''
}
handleChange = (event) => {
this.setState({
[event.target.name]: event.target.value,
post: {
title: this.state.title,
content: this.state.content,
author: this.state.author
}
});
}
render() {
return (
<div className="NewPost">
<h1>Add a Post</h1>
<label>Title</label>
<input type="text" name="title" value={this.state.title} onChange={this.handleChange} />
<label>Content</label>
<textarea rows="4" name="content" value={this.state.content} onChange={this.handleChange} />
<label>Author</label>
<select name="author" value={this.state.author} onChange={this.handleChange}>
<option value="Max">Max</option>
<option value="Manu">Manu</option>
</select>
<button
onClick={this.props.newPostCreated(this.state.post)}>
Add Post
</button>
</div>
);
}
}
您需要將其編寫為:
onClick={() => this.props.newPostCreated(this.state.post)}>
否則,每次在執行setState(..)
時調用render()
時,它將在JSX {..}
內部執行。 出於性能原因,最好沒有箭頭功能的方式編寫它。
class NewPost extends Component {
// ..
onBtnClick = () => {
this.props.newPostCreated(this.state.post);
};
render() {
return (
// ..
<button onClick={this.onBtnClick}>Add Post</button>
</div>
);
}
}
我還發現您的狀態構造和handleChange函數有點奇怪和錯誤。 我將這樣編寫類:
class NewPost extends Component {
state = {
post: {
title: "",
content: "",
author: "Max"
}
};
handleChange = ({ target }) => {
this.setState(prevState => ({
post: {
...prevState.post,
[target.name]: target.value
}
}));
};
onBtnClick = () => {
this.props.newPostCreated(this.state.post);
};
render() {
const { post: { content, title, author } } = this.state;
return (
<div className="NewPost">
<h1>Add a Post</h1>
<label>Title</label>
<input
type="text"
name="title"
value={title}
onChange={this.handleChange}
/>
<label>Content</label>
<textarea
rows="4"
name="content"
value={content}
onChange={this.handleChange}
/>
<label>Author</label>
<select
name="author"
value={author}
onChange={this.handleChange}
>
<option value="Max">Max</option>
<option value="Manu">Manu</option>
</select>
<button onClick={this.onBtnClick}>Add Post</button>
</div>
);
}
}
您應該將updatedPostsHandler
調用作為一個函數添加到子組件。 因此,當您單擊子組件上的按鈕時,它將調用一個函數,該函數將執行一個函數。
嘗試如下添加您的updatedPostsHandler:
<NewPost newPostCreated={() => this.updatedPostsHandler} />
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