reactjs - React.JS Ref 中的 Ref 错误 - createRef、useRef 和 using Refs

Question

我正在尝试通过 React 使用 ref 属性。我的浏览器出现奇怪的错误，但我无法弄清楚问题出在哪里。谁能向我解释一下为什么我会收到此错误:

Error: Invariant Violation: addComponentAsRefTo(...): Only a ReactOwner can have refs. This usually means that you're trying to add a ref to a component that doesn't have an owner (that is, was not created inside of another component's render method). Try rendering this component inside of a new top-level component which will hold the ref.

当我有这个代码时:

/**
* @jsx React.DOM
*/
(function(){
var react = require('react');


var App = react.createClass({

    render: function() {
        return (
            <h1 ref="myRef">This is a test</h1>
        );
    }

});

react.render(
    <App />,
    document.body
);
}());

Answer 1

您的代码是正确的。

工作中的 jsFiddle: http://jsfiddle.net/reactjs/69z2wepo/

var App = React.createClass({

    render: function() {
        return (
            <h1 ref="myRef">This is a test</h1>
        );
    }

});

React.render(
    <App />,
    document.body
);

根据错误消息，您将引用放置在非拥有的元素上，但在您提供的代码中，h1 由App 拥有。您的代码与上面粘贴的代码不同吗？

注意(from the docs):

In React, an owner is the component that sets the props of other components ... 
It's important to draw a distinction between the owner-ownee relationship and the parent-child relationship.