[英]Add Form Fields Dynamically — ReactJs
我的要求是动态添加表单字段。 我可以在点击按钮+添加标题时动态添加表单组。
在该表单组中,我有一个按钮+添加内容 ,点击该按钮将新的输入元素添加到该组。
我能够相应地修改JSON并记录相同的状态并更新状态。 但我的观点没有按预期呈现。
任何帮助将受到高度赞赏。
Stackblitz: https ://stackblitz.com/edit/react-utjwsu ? sombed = 1& file = index.js
/ 代码相同 /
import React, { Component } from 'react';
import { render } from 'react-dom';
import { Form, FormGroup, Label, Progress,Button } from 'reactstrap';
import Hello from './Hello';
import './style.css';
const byPropKey = (propertyName, value) => () => ({
[propertyName]: value,
});
class App extends Component {
constructor(props) {
super(props);
this.state = {
name: 'React',
Information:'',
ImageUrl:'',
isUploading: false,
isUploaded: true,
showProgress: false,
progress: 0,
avatarUrl:'',
ref:'WhitePapersItems',
formValid: false,
content: [{Heading: "", Content: [{value:""}]}]
};
this.AddContentBox = this.AddContentBox.bind(this);
this.handleChange = this.handleChange.bind(this);
this.AddContentInput = this.AddContentInput.bind(this);
}
AddContentBox(){
return this.state.content.map((element,i)=>(
<div className="header-content" key={i} >
<div className="heading-content-wrapper">
<FormGroup>
<Label className="set-label-pos upload-img" for="Heading">Heading</Label>
<input className="form-control" onChange={this.handleChange.bind(this, i)}
type="text"/>
</FormGroup>
<FormGroup>
<Label className="set-label-pos upload-img" for="Heading">Content</Label>
<input className="form-control" onChange={this.handleChange.bind(this, i)}
type="text"/>
</FormGroup>
{/* {this.AddContentInput} */}
<FormGroup>
<Button color="success" onClick={this.AddContentInput.bind(this,i)}>+ Add Content</Button>
</FormGroup>
</div>
</div>
))
}
handleChange(i, e) {
const { Heading, value } = e.target;
let content = [...this.state.content];
content[i] = {...content[i], [Heading]: value};
this.setState({ content });
}
AddContentInput(index, val){
console.log('Add ContentInput triggered',val,index);
const contents = this.state.content;
contents[index].Content.push({value:''});
this.setState({content:contents});
const item = this.state.content[index].Content;
console.log('item', item)
return item.map((element, i)=>(
<FormGroup>
<Label className="set-label-pos upload-img" for="Heading">Content</Label>
<input className="form-control" type="text"/>
</FormGroup>
))
// console.log(this.state)
// this.addContentField(index);
}
addHeading(event){
event.preventDefault();
this.setState(prevState => ({
content: [...prevState.content, { Heading: "", Content: [{value:""}] }]
}))
this.AddContentBox();
}
render() {
return (
<div>
<Form onSubmit={this.onSubmit}>
<FormGroup>
<Label className="set-label-pos upload-img" for="Information">Information</Label>
<textarea className="form-control" rows="10" onChange={event => this.setState(byPropKey('Information', event.target.value))}
type="text"/>
</FormGroup>
{this.AddContentBox()}
<div className="add-heading-button">
<Button color="primary" onClick={this.addHeading.bind(this)}>+ Add Heading</Button>
</div>
<FormGroup>
<input type="hidden" value={this.state.ImageUrl} onChange={event => this.setState(byPropKey('ImageUrl', event.target.value))}/>
</FormGroup>
<Button className="btn btn-danger" size="lg" type="submit">+ Add White Papers Item</Button>
</Form>
</div>
);
}
}
render(<App />, document.getElementById('root'));
为那些可能遇到过这种情况的人回答我自己的问题。
更新我的stackblitz: https ://stackblitz.com/edit/react-utjwsu ? sombed = 1& file = index.js
我没有渲染所有内容字段而只是尝试渲染一个。
/ 代码在这里 /
import React, { Component } from 'react';
import { render } from 'react-dom';
import { Form, FormGroup, Label, Progress,Button } from 'reactstrap';
import Hello from './Hello';
import './style.css';
const byPropKey = (propertyName, value) => () => ({
[propertyName]: value,
});
class App extends Component {
constructor(props) {
super(props);
this.state = {
name: 'React',
Information:'',
ImageUrl:'',
isUploading: false,
isUploaded: true,
showProgress: false,
progress: 0,
avatarUrl:'',
ref:'WhitePapersItems',
formValid: false,
content: [{Heading: "", Content: [{value:""}]}]
};
this.AddContentBox = this.AddContentBox.bind(this);
this.AddContentInput = this.AddContentInput.bind(this);
//this.addContentTextBox = this.addContentTextBox.bind(this);
}
AddContentInputFields(element) {
return element.Content.map(content => {
return (
<FormGroup>
<Label className="set-label-pos upload-img" for="Heading">Content</Label>
<input className="form-control" type="text"/>
</FormGroup>
);
})
}
AddContentBox(){
return this.state.content.map((element,i)=>(
<div className="header-content" key={i} >
<div className="heading-content-wrapper">
<FormGroup>
<Label className="set-label-pos upload-img" for="Heading">Heading</Label>
<input className="form-control" type="text"/>
</FormGroup>
{ this.AddContentInputFields(element) }
<FormGroup>
<Button color="success" onClick={this.AddContentInput.bind(this,i)}>+ Add Content</Button>
</FormGroup>
</div>
</div>
))
}
handleChange(i, e) {
const { Heading, value } = e.target;
let content = [...this.state.content];
content[i] = {...content[i], [Heading]: value};
this.setState({ content });
}
AddContentInput(index, val){
console.log('Add ContentInput triggered',val,index);
const contents = _.cloneDeep(this.state.content);
contents[index].Content.push({value:''});
const item = contents[index].Content;
console.log('item', item);
this.setState({content:contents});
//this.addContentTextBox(item);
}
// addContentTextBox(item){
// return item.map((element, i)=>(
// <FormGroup>
// <Label className="set-label-pos upload-img" for="Heading">Content</Label>
// <input className="form-control" type="text"/>
// </FormGroup>
// ));
// }
addHeading(event){
event.preventDefault();
this.setState(prevState => ({
content: [...prevState.content, { Heading: "", Content: [{value:""}] }]
}))
this.AddContentBox();
}
render() {
return (
<div>
<Form onSubmit={this.onSubmit}>
<FormGroup>
<Label className="set-label-pos upload-img" for="Information">Information</Label>
<textarea className="form-control" rows="10" onChange={event => this.setState(byPropKey('Information', event.target.value))}
type="text"/>
</FormGroup>
{this.AddContentBox()}
<div className="add-heading-button">
<Button color="primary" onClick={this.addHeading.bind(this)}>+ Add Heading</Button>
</div>
<FormGroup>
<input type="hidden" value={this.state.ImageUrl} onChange={event => this.setState(byPropKey('ImageUrl', event.target.value))}/>
</FormGroup>
<Button className="btn btn-danger" size="lg" type="submit">+ Add White Papers Item</Button>
</Form>
</div>
);
}
}
render(<App />, document.getElementById('root'));
这不能正常工作的原因是因为您直接修改this.state
。 React不会自动重新渲染,因为你没有告诉它状态已经改变了。
您需要调用this.setState()
来设置新状态。
如果要添加到对象(例如this.state.content
,则需要确保获取对象的副本(使用类似_.cloneDeep()
)以确保不修改现有对象。
希望这足以解释您能够解决您的问题。
更新:您使用以下代码间接修改状态: const contents = this.state.content; contents[index].Content.push({value:''});
const contents = this.state.content; contents[index].Content.push({value:''});
contents
是一个变量,它不是this.state.content
的副本,它是对它的引用。 因此,将值推入对象实际上是直接修改状态。 我很抱歉没有在原来的答案中说清楚
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.