Question

问题在于状态未定义。 nextProps.userid的第一个控制台日志显示正确的用户标识，但它没有更改状态，第二个控制台日志返回null。

class Profile extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      user: this.props.userid,
    };
  }

  componentWillReceiveProps(nextProps){
    console.log('PROFILE USERID', nextProps.userid)
    const userid = nextProps.userid
    this.setState({user:userid})
    console.log('PROFILE USERID 2', this.state.user)
  }

Answer 1

setState是异步的。因此，您不能指望在setState之后立即更改状态值。如果您在setState之后立即记录您的状态，那么它将显示您之前的状态。如果您想查看状态的更新值，请尝试将回调传递给this.setState({user:userid}, () => { console.log('PROFILE USERID 2', this.state.user) });，如此

  if(await userManager.UpdateSecurityStampAsync(user.Id) != IdentityResult.Success)
        {
            // https://www.stevejgordon.co.uk/asp-net-core-identity-token-providers
            // we update it to effectively reset all the token validation stuff
            return IdentityResult.Failed("failed to update the security stamp");
        }

        // Send token - this may throw but thats ok as we just rollback
        string code = await userManager.GenerateTwoFactorTokenAsync(user.Id, "twilio");
        await userManager.SmsService.SendAsync(new Microsoft.AspNet.Identity.IdentityMessage
        {
            Destination = user.UserName,
            Body = "Your security code is: " + code
        });

反应道具不更新状态

1 个答案: