mapStateToProps 不会改变状态

IT技术 reactjs redux
2021-05-11 14:09:27

我是 redux 的新手并想学习它,我想在成功登录后重定向到仪表板内容,这是我的代码:

class Dashboard extends Component {
  state = {
    logged: false
  };
render() {
    const { classes } = this.props;
    console.log(this.state.logged)

    return (
<div>
{this.state.logged ?
<div>
<p>Hello</p>
</div>
: Login()
</div>
)}
}

const mapStateToProps = (state, props) => {
  return {
      logged: state.logged
  }
}

export default connect(mapStateToProps)(Dashboard)

减速器:

const initialState = {
    login: [],
    logged: false
}

function rootReducer(state = initialState, action) {
    switch(action.type) {
        case VALIDATE_LOGIN:
            return  {
                    // logged: action.text.name == "a" && action.text.password == "b" ? true : false,
                    ...state,
                    logged: true
                }
        default:
            return state
    }

}

export default rootReducer

为什么它不想更改仪表板的状态并呈现正确的内容?谢谢

在这里编辑我添加代码,在那里我调度我的减速器:登录:

class Login extends Component {
  state = {
    name: "",
    password: ""
  };


  handleLogin = () => {
    this.props.LogIn(this.state)
  }

  render() {
    return (
      <div>
        <Typography variant="h3">
          Login Form
        </Typography>
        <form>
          <TextField label="name" onChange={el => this.setState({name: el.target.value})} />
          <TextField label="password" type="password" onChange={el => this.setState({password: el.target.value})} />
          <Button onClick={this.handleLogin}>Login</Button>
        </form>
      </div>
    );
  }
}

const dispatchToProps = dispatch => {
  return {
    LogIn: login => dispatch(LogIn(login))
  }
}

export default connect(null, dispatchToProps)(Login);

当我尝试控制台登录 mapStateToProps 时,我可以看到记录已更改为 true,但不幸的是在仪表板上没有可见效果。我的想法是,也许它在更改状态后不会重新渲染,但我不知道......

2个回答

mapStateToProps将“状态”(redux 状态)映射到“props”(组件props)。不是“状态”到“状态”

class Dashboard extends Component {
  render() {
    const { classes, logged } = this.props

    return (
      <div>
        {logged ? (
          <div>
            <p>Hello</p>
          </div>
        ) : (
          Login()
        )}
      </div>
    )
  }
}

mapStateToProps如果您不实际使用它,也不要指定第二个参数这会阻止由 完成的优化react-redux

const mapStateToProps = (state) => {
  return {
      logged: state.logged
  }
}

改变

{this.state.logged ?
<div>
<p>Hello</p>
</div>
: Login()
</div>
)}

{this.props.logged ?
<div>
<p>Hello</p>
</div>
: Login()
</div>
)}