react之传递数据的几种方式props传值、路由传值、状态提升、redux、context

react之传递数据的几种方式

1、父子传值

父传值：<子的标签 value={‘aaa‘} index={‘bbb‘}></子的标签>

子接值：<li key={this.props.index}>{this.props.value}</li>

不止可以传值也可以传递方法：

父：方法={this.方法}

子：{this.props.方法.bind(this)}

传来的参数子组件可以使用，此处用{value,index}等解构赋值省去this.props

此处的子组件利用这个deleteItem方法向父元素传递了index

父传子，子为styled

父：

　　<Lun pic={this.state.good ? this.state.good.image : ‘‘}></Lun>

子：

　　const Lun = styled.div`

　　　　width:100%;

　　　　height:375px;

　　　　background:url(‘${props => props.pic}‘) center no-repeat;

　　　　background-size: cover;

　　`

2、路由传值

import { BrowserRouter } from ‘react-router-dom‘

包在最外层，我放在了我的react项目的index.js里

方法一：/路径/:自己起的要传的值的名字

父组件：import { Route, Switch, Redirect } from ‘react-router-dom‘

class App extends Component {
  render() {
    return (
      <Switch>
        <Redirect exact from="/" to="/car"></Redirect>
        <Route path=‘/home‘ component={Bar}/>
        <Route path="/shopDetail/:shopId/:shopName/:shopNote/:shopPic" component={ShopDetail} />
        <Route path=‘/noteDetail/:noteId‘ component={NodeDe} />
        <Route path=‘/goodDetail/:goodId/:shopId‘ component={GoodDetail} />
        <Route path=‘/car‘ component={Car} />
      </Switch>
    );
  }
}

export default App;

         子组件：          <LogoCon>
            <div>
              <img src=‘https://ci.xiaohongshu.com/98320dbb-536e-451a-a53f-98724b56d380?imageView2/3/w/420/h/600/format/jpg/q/90‘ />
              <div>
                <h2>{this.props.match.params.shopName}</h2>
                <h6></h6>
                <h5>{this.props.match.params.shopNote}篇笔记</h5>
              </div>
              <a href="javascript:void(0)">关注</a>
            </div>
          </LogoCon>

方法二：

var data = {id:0,name:‘lili‘,age:16};

data = JSON.stringify(data);

var path = `/user/${data}`;

<Link to={path}>用户</Link>

var data = this.props.location.query;

var {id,name,age} = data;

L：父组件为<A></A>

　  子组件为<B></B>

在父组件中调用子组件：

<A>

　　<B {...props}></B>

</A>

以此类推。

已我自己写的一个小demo为例子：

大概项目大概如第二张图，具体应用体现在goodDetail文件夹内

新建一个store文件夹，做一个数据处理的汇总

store/redecers.js

store/redecers.js

import { combineReducers } from ‘redux‘

import shop from ‘pages/shop/reducer‘
import car from ‘pages/goodDetail/reducer‘

export default combineReducers({
    shop,
    car
})

store/index.js

import { createStore, applyMiddleware } from ‘redux‘

import thunk from ‘redux-thunk‘

import reducers from ‘./reducers‘

const store = createStore(reducers, applyMiddleware(thunk))

export default store

goodDetail/actionType.js

export const GET_CAR_DATA = ‘car/get_car_data‘

goodDetail/actionCreator.js

import { GET_CAR_DATA } from ‘./actionType‘

export const loadCarDataSync = (goods) => {
    //console.log(goods)
    return {
      type: GET_CAR_DATA,
      goods:goods
    }
  }

  export const loadCarDataAsync = (dispatch,obj) => {
    // console.log(1)
    //console.log(obj)
    return () => {
        dispatch(loadCarDataSync(obj))
    }
  }

goodDetail/reducer.js(处理数据)

import {GET_CAR_DATA} from ‘./actionType‘

const defaultState = {
    goods:[{
      shopName: "豌豆公主海外美妆集合店",
      he:[
        { image: "https://img.xiaohongshu.com/items/[email protected]_320w_320h_1e_1c_0i_90Q_1x_2o.jpg",
          introduce: "clé de Peau Beauté肌肤之钥 沁肌紧肤水磨精华液 170ml",
          kuSave: 296161,
          num: 4,
          price: 609
        }
      ]
    }
  ]
}

export default (state=defaultState, action) => {
    if (action.type === GET_CAR_DATA) {
      if(!!state.goods){
        const obj = state.goods.find(v => v.shopName === action.goods.shopName )
        if(!!obj){
          const same = obj.he.find(i => i.introduce === action.goods.he[0].introduce )
          console.log(obj)
          if(!!same){
            same.num++;
          }else{
            obj.he.push(...action.goods.he)
          }
          return {
            goods: [...state.goods]
          }
        }else{
          return {
            goods: [...state.goods,action.goods]
          }
        }
      }
      else{
        return {
          goods: [action.goods]
        }
      }
    }

    return state
}  

整个项目最外面的index.html中引入

import store from ‘./store‘

在goodDetail/goodDetai.js中

import { connect } from ‘react-redux‘

import {
    Link,
    withRouter
} from ‘react-router-dom‘

import { loadCarDataAsync } from ‘./actionCreator‘

const mapState = (state) => {
    //console.log(state)
    return {
      goods: state.car.goods
    }
}

const mapDispatch = (dispatch) => {
    return {
        loadCategories (obj) {
            //console.log(obj)
            dispatch(loadCarDataAsync(dispatch,obj))
        }
    }
}

中间代码省略，在你需要的地方调用
          this.props.loadCategories(
                {
                    shopName:this.state.good.vendor_name,
                    he:[{
                        image:this.state.good.image,
                        introduce:this.state.good.desc,
                        price:this.state.good.discount_price,
                        kuSave:this.state.good.fav_info.fav_count,
                        num:Number(this.refs.goodNum.value)
                    }]
                }
            )    （参数可传可不传，不传的话，其余对应的地方记得修改）

export default withRouter(connect(mapState, mapDispatch)(GoodDetail))

不合适修改数据

更适合共享数据

getChildContext()

祖先组件：

　　1>import PropsTypes from ‘prop-types‘

　　2>static childCOntextTypes={

　　　　XX:PropsTypes.string

　　　}

　　3>getChildContext(){

　　　　return {XX:xx}

　　　}

　　4>引入一个子组件

子组件接收：

　　this.context.XX

原文地址：https://www.cnblogs.com/yangyangxxb/p/10035834.html