你必须检查this.props.mandatory_fields.updateNeeded的componentDidUpdate钩。更改 Redux 状态后，组件将更新。所以，你必须检查props的componentDidUpdate，而不是对你呼叫调度后。你可以看到我的代码：

componentDidUpdate(prevProps, prevState, snapshot) {
    console.log(
        'this.props.mandatory_fields.updateNeeded -- ' +
        this.props.mandatory_fields.updateNeeded
    )
}

您的代码将变为：

class CompleteProfile extends Component {
  state = {
    completeProfile: false,
  }

  componentDidMount(){
    let { dispatch, session } = this.props
    dispatch(getMandatoryFields(session.username))
  }

  componentDidUpdate() {
    console.log(
      'this.props.mandatory_fields.updateNeeded -- ' +
        this.props.mandatory_fields.updateNeeded
    )
    if (this.props.mandatory_fields.updateNeeded !== false) {
      this.setState({
        completeProfile: this.props.mandatory_fields.updateNeeded,
      })
    }
  }
...
...
....
const mapStateToProps = state => ({
  mandatory_fields: state.User.mandatory_fields,
  session: state.User.session,
})

export default connect(mapStateToProps)(CompleteProfile)

使用@Max 的解决方案，您的全新代码应该是这样的：

componentDidUpdate(prevProps) {
  let { dispatch, session } = this.props
  dispatch(getMandatoryFields(session.username))
  console.log(
    'this.props.mandatory_fields.updateNeeded -- ' +
      this.props.mandatory_fields.updateNeeded
  );
  if (!prevProps.mandatory_fields.updateNeeded && this.props.mandatory_fields.updateNeeded) {
    this.setState({
      completeProfile: this.props.mandatory_fields.updateNeeded,
    })
  }
}