反应:如何通知父母更改 [英] React: how to notify parent for changes

问题描述

我正在尝试将引导程序包装到具有集成表单验证的组件中.

简短:假设我有

<现场组><字段规则={'required'}/></FieldGroup></表格>

一旦Field通过验证，我如何通知FieldGroup(父节点)添加一个类?

我在这里

创建了一个简化的codepen版本

我想根据验证状态，然后更改 FieldGroup 的状态，以便我可以正确更改类名.(添加 has-warning has-danger 等)并最终将类添加到 Form 组件中.

解决方案

您需要将 callback 传递给子组件.我只是分叉了你的 codepen 并添加了一些如下片段.

http://codepen.io/andretw/pen/xRENee

这里是主要概念，在 "parent" 组件中创建一个回调函数并将其传递给 "child" 组件

即子组件需要一个额外的道具来获取回调:

<现场组><Field rules={'required'} cb={yourCallbackFunc}/></FieldGroup></表格>

在(父)中:

class FieldGroup 扩展 React.Component{构造函数(道具){超级(道具)；this.state = {颜色:'蓝色'}}CB(味精){console.log('在这里做事', msg)}使成为() {const childrenWithProps = React.Children.map(this.props.children,孩子 =>React.cloneElement(child, {cb: 这个.cb}))返回 (
<标签>字段{ childrenWithProps }
);}};

在(子)中:

class 字段扩展 React.Component{构造函数(道具){超级(道具)；this.state = {空:真实}this.validate = this.validate.bind(this);}验证(e){让 val = e.target.value;控制台日志(！val)；this.setState({empty: !val});//这里通知父级添加颜色样式！//请在此处回拨，否则您可能不需要返回.this.props.cb(val)返回 !val;}使成为() {返回 (<div><input type='text' onBlur ={(event) =>this.validate(event)}/>{this.state.empty &&'空的'}

);}};

而且你可以在回调函数中做你想做的事情.(你也可以从 传一个回调给孙子，让它工作，但你需要重新考虑它的设计好不好.)

I'm trying to wrap bootstrap into components with integrated form validation.

short: Let's say I have

<Form>
  <FieldGroup>
     <Field rules={'required'}/>
  </FieldGroup>
</Form>

Once Field pases validation, how can I notify FieldGroup (parent node) to add a class?

I created a simplified codepen version here

I would like depending on validation status, then change the state of FieldGroup So I can properly change the class name. (add has-warning has-danger etc) and ultimately add class to the Form component.

解决方案

You need to pass a callback to the child component. I just forked your codepen and added some snippet as below.

http://codepen.io/andretw/pen/xRENee

Here is the main concept, Make a callback function in "parent" component and pass it to the "child" component

i.e. The child component needs an extra prop to get the callback:

<Form>
  <FieldGroup>
     <Field rules={'required'} cb={yourCallbackFunc}/>
  </FieldGroup>
</Form>

In <FieldGroup /> (parent):

class FieldGroup extends React.Component{
  constructor(props){
    super(props);
    this.state = {
      color: 'blue'
    }
  }

  cb (msg) {
    console.log('doing things here', msg)
  }

  render() { 
    const childrenWithProps = React.Children.map(this.props.children,
     child => React.cloneElement(child, {
       cb: this.cb
     })
    )
    return (
      <div class='fields-group'>
        <label> field </label>
        { childrenWithProps }
      </div>
    );
  }
};

In <Field /> (child):

class Field extends React.Component{
  constructor(props){
    super(props);
    this.state = {
      empty: true
    }
    this.validate = this.validate.bind(this);
  }

  validate(e){
    let val = e.target.value;
    console.log(!val);
    this.setState({empty: !val});
    //here to notify parent to add a color style!

    // do call back here or you may no need to return.
    this.props.cb(val)

    return !val;
  }

  render() {
    return (
      <div>
        <input type='text' onBlur ={(event) => this.validate(event)}/>
        {this.state.empty && 'empty'}
      </div>
    );
  }
};

And you can do the things you want in the callback function. (You can also pass a callback from <Form /> to the grandson and get it work, but you need to rethink the design of it is good or not.)

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