Question

我有一个用户列表，其中包含每个用户的姓名和电子邮件ID。我想在.map()状态变量上使用userlist方法显示它。我创建了displayusers()函数来显示用户，但是我没有编译错误。

代码：

import React, { Component } from 'react';

class App extends Component {

  constructor(props){
    super(props);
    this.state = {
          userlist:[
          {'name':'Rohan Singh', 
           'email':'rohan@gmail.com'
          },

          {'name':'Mohan Singh', 
           'email':'mohan@gmail.com'
          },

          {'name':'Rakesh Roy', 
           'email':'rakesh@gmail.com'
          },

          {'name':'Sunil Shah', 
           'email':'sunil@gmail.com'
          }]
    }
  }

  displayusers(){
        return this.state.userlist.map( user => {
          return(
            <div className="item-card">
               <div className="sub">    
                    <div className="type">Username: {user.name}</div>
                    <div className="members">Email: {user.email}</div>
               </div>
            <div className="del-wrap">
                <img src={require("../../images/cancel.svg")}/>
            </div>
           </div>
            );
        })
  }

  render() {
        return(
          <div className="users-wrap">
                <h1>Users</h1>
                <div className="task-content">
                    <div className="user-wrap">
                        <div className="users">
                             {this.displayusers()}
                        </div>
                    </div>
                </div> 
          </div>
        );
    }
}

export default App;

Answer 1

我认为您忘了向元素添加key属性，并且地图函数中缺少</div>结束标记。

查看更正后的代码：

displayusers(){
    return this.state.userlist.map( user => {
        return(
            <div className="item-card" key={user.name}>
                <div className="sub">    
                    <div className="type">Username: {user.name}</div>
                    <div className="members">Email: {user.email}</div>
                </div>
                <div className="del-wrap">
                    <img src={require("../../images/cancel.svg")}/>
                </div>
            </div>
        );
    });
}

Answer 2

您需要将displayusers功能绑定到 this 。您可以在构造函数中执行此操作。

按以下方式更新您的代码：

import React, { Component } from 'react';

class App extends Component {

constructor(props){
 super(props);
 this.state = {
      userlist:[
      {'name':'Rohan Singh', 
       'email':'rohan@gmail.com'
      },

      {'name':'Mohan Singh', 
       'email':'mohan@gmail.com'
      },

      {'name':'Rakesh Roy', 
       'email':'rakesh@gmail.com'
      },

      {'name':'Sunil Shah', 
       'email':'sunil@gmail.com'
      }]
  };

  this.displayusers = this.displayusers.bind(this); // you need to add this line
 }

 displayusers(){
    return this.state.userlist.map((user, index) => {
      return(
        <div className="item-card" key={index}>
           <div className="sub">    
                <div className="type">Username: {user.name}</div>
                <div className="members">Email: {user.email}</div>
           </div>
        <div className="del-wrap">
            <img src={require("../../images/cancel.svg")}/>
        </div>
        );
    })
}

render() {
    return(
      <div className="users-wrap">
            <h1>Users</h1>
            <div className="task-content">
                <div className="user-wrap">
                    <div className="users">
                         {this.displayusers()}
                    </div>
                </div>
            </div> 
      </div>
    );
  }
}

export default App;

无法使用reactjs中的地图显示列表项？

2 个答案: