使react重绘所有组件或部分组件

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      count: 0
    };
  }

  handleClick() {
    this.setState({ count: this.state.count + 1 });
  }

  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <button onClick={() => this.handleClick()}>Increment</button>
      </div>
    );
  }
}

class MyComponent extends React.Component {
  handleClick() {
    this.forceUpdate();
  }

  render() {
    return (
      <div>
        <p>Component</p>
        <button onClick={() => this.handleClick()}>Force Update</button>
      </div>
    );
  }
}

const MyContext = React.createContext();

class MyComponent extends React.Component {
  render() {
    return (
      <MyContext.Provider value={/* 上下文数据 */}>
        <MyChildComponent />
      </MyContext.Provider>
    );
  }
}

class MyChildComponent extends React.Component {
  render() {
    return (
      <MyContext.Consumer>
        {value => (
          <div>
            <p>Context Value: {value}</p>
          </div>
        )}
      </MyContext.Consumer>
    );
  }
}