Question

我有一个带有模拟登录名的导航栏组件，它使我从模式中获取用户电子邮件，但是当我向signinmenu组件发送属性时，电子邮件显示为未定义。

我还发送了一个登出功能，该功能正常运行，但字符串电子邮件显示为未定义

导航栏组件

render() {
    const { auth } = this.props;
    const authenticated = auth.authenticated;

    return (
      <Menu inverted fixed="top">
        <Container>
          <Menu.Item as={Link} to="/" header>
            <img src="/assets/images/logo.png" alt="logo" />
            Re-vents
          </Menu.Item>
          <Menu.Item as={NavLink} to="/events" name="Events" />
          <Menu.Item as={NavLink} to="/test" name="Test" />
          {authenticated &&
          <Menu.Item as={NavLink} to="/people" name="People" />}

          {authenticated &&
          <Menu.Item>
            <Button
              as={Link}
              to="/createEvent"
              floated="right"
              positive
              inverted
              content="Create Event"
            />
          </Menu.Item>}
          {authenticated ? (
            <SignedInMenu currentUser={auth.currentUser} signOut={this.handleSignOut} /> 
          ) : (
            <SignedOutMenu signIn={this.handleSignIn} register={this.handleRegister} />
          )}
        </Container>
      </Menu>
    );
  }
}

SignInMenu组件

import React from 'react';
import { Menu, Image, Dropdown } from 'semantic-ui-react';
import { Link } from 'react-router-dom'

const SignedInMenu = ({signOut, currentuser}) => {
  console.log(currentuser)
  return (
    <Menu.Item position="right">
      <Image avatar spaced="right" src="/assets/images/user.png" />
      <Dropdown pointing="top left" text={currentuser}>
        <Dropdown.Menu>
          <Dropdown.Item text="Create Event" icon="plus" />
          <Dropdown.Item text="My Events" icon="calendar" />
          <Dropdown.Item text="My Network" icon="users" />
          <Dropdown.Item text="My Profile" icon="user" />
          <Dropdown.Item as={Link} to='/settings' text="Settings" icon="settings" />
          <Dropdown.Item onClick={signOut} text="Sign Out" icon="power" />
        </Dropdown.Menu>
      </Dropdown>
    </Menu.Item>
  );
};

export default SignedInMenu;


I know the string is on the props but when I tried to show in the text attribute or console.log appears as undefined

Answer 1

这是一种错别字-您在上级组件中将道具作为currentUser传递，在子级中将其作为currentuser接受。您需要

<SignedInMenu currentuser={auth.currentUser} signOut={this.handleSignOut} />

避免这类问题很棘手，但是在某些情况下使用React PropTypes可以有所帮助，您可以考虑将它们添加到项目中。

Answer 2

SignedInMenu是一个功能组件，其所有道具都包含在第一个参数中。所以您需要像这样使用它：

SignedInMenu = (props) => {
  return <h1>Hello, {props.name}</h1>;
}

React组件中的未定义参数

2 个答案: