面临类型错误：使用上下文 API 时，渲染不是 function

Question

I am new to React ans was learning Context API and during the use of it I faced this error TypeError: render is not a function. I also found the this answer React Context: TypeError: render is not a function in the platform which is close to my problem but no result. Here is the code I am using:

import React, { Component } from "react";
import MyContext from "../../Containers/Context/Context";
class Track extends Component {
  render() {
    return (
      <MyContext>
        {value => {
          return <div>{value.heading}</div>;
        }}
      </MyContext>
    );
  }
}

export default Track;

---

import React, { Component } from "react";

const Context = React.createContext();

export class MyContext extends Component {
  state = { track_list: [], heading: "Top Ten Tracks" };
  render() {
    return (
      <Context.Provider value={this.state}>
        {this.props.children}
      </Context.Provider>
    );
  }
}

export default MyContext = Context.Consumer;

---

import React, { Component, Fragment } from "react";
import "./App.css";
import Header from "../src/Components/Header/Header";
import Search from "../src/Components/Search/Search";
import Tracks from "../src/Components/Tracks/Tracks";
import { BrowserRouter as Router, Route, Link, Switch } from "react-router-dom";
import NotFound from "./Components/NotFound/NotFound";
import MyContext from "./Containers/Context/Context";

class App extends Component {
  render() {
    return (
      <MyContext>
        <Router>
          <Fragment>
            <Header />
            <div className="container">
              <Search />
              <Switch>
                <Route exact path="/" component={Tracks} />
                <Route component={NotFound} />
              </Switch>
            </div>
          </Fragment>
        </Router>
      </MyContext>
    );
  }
}

export default App;

Answer 1

Your export and import statements are problematic.

first you export class MyContext then you immediately overwrite MyContext with Context.Consumer .

Fix your export statements and then fix your imports. import the Context.Consumer in file Track , and import the Context.Provider in file App

Containers/Context/Context.js

import React, { Component } from "react";

const Context = React.createContext();

class MyContextProvider extends Component {
  state = { track_list: [], heading: "Top Ten Tracks" };
  render() {
    return (
      <Context.Provider value={this.state}>
        {this.props.children}
      </Context.Provider>
    );
  }
}

const MyContextConsumer = Context.Consumer;

export {MyContextProvider,MyContextConsumer};

Track.js

import React, { Component } from "react";
import {MyContextConsumer} from "../../Containers/Context/Context";
class Track extends Component {
  render() {
    return (
      <MyContextConsumer>
        {value => {
          return <div>{value.heading}</div>;
        }}
      </MyContextConsumer>
    );
  }
}

export default Track;

App.js

import React, { Component, Fragment } from "react";
import "./App.css";
import Header from "../src/Components/Header/Header";
import Search from "../src/Components/Search/Search";
import Tracks from "../src/Components/Tracks/Tracks";
import { BrowserRouter as Router, Route, Link, Switch } from "react-router-dom";
import NotFound from "./Components/NotFound/NotFound";
import {MyContextProvider} from "./Containers/Context/Context";

class App extends Component {
  render() {
    return (
      <MyContextProvider>
        <Router>
          <Fragment>
            <Header />
            <div className="container">
              <Search />
              <Switch>
                <Route exact path="/" component={Tracks} />
                <Route component={NotFound} />
              </Switch>
            </div>
          </Fragment>
        </Router>
      </MyContextProvider>
    );
  }
}

export default App;