反应，用道具循环

Question

在方法render()中，我用this.state.objects.map(item, id)调用子元素的循环

conversationTemplate = this.state.objects.map(function (item, index) {

            return (
                <Panel eventKey={index}>
                    <h4> {item.msg_text} </h4>
                    <ReactMessageChat conversationId={item.pk}> {item.pk} </ReactMessageChat>
                </Panel>
           )
}

当新项出现时，呈现重新引导，但是子元素conversationId中的ReactMessageChat始终作为循环中的第一个。

class ReactMessageChat extends React.Component {
constructor(props) {
    super(props);
    this.state = {
        objects: [],
        loaded: false,
    };
    this.addNewMsg = this.addNewMsg.bind(this);
    this.subscribe = this.subscribe.bind(this);
}


subscribe() {
    return centrifuge;
}


loadDataFromServer(conversationId) {
    let self = this;
    var url = '/api/support_messages/?msg_conversation=' + conversationId
    ...
}
addNewMsg(message) {
    let self = this;
    if (message.msg_conversation == self.props.conversationId) {
        var newArray = self.state.objects;
        newArray.push(message);
        self.setState({objects: newArray});
    }
}

componentDidMount() {
    this.loadDataFromServer(this.props.conversationId);
    this.subscribe();
}

render() {
    let self = this;
    var messagesTemplate;
    if (self.state.objects.length > 0) {
        let reversedObjects = self.state.objects.reverse();
        messagesTemplate = reversedObjects.map(function (item, index) {
            return (
                <li className="list-group-item" key={index}>    
                    {item.msg_text}</li>
            )
        })
    }

Answer 1

这是因为在不同的循环方法中，必须将属性"key“给重复元素。https://facebook.github.io/react/docs/lists-and-keys.html