2021更新：

自从我添加这个响应以来，已经有一段时间了，而且由于它似乎仍然引起了一些兴趣，我想我会将它更新到更新的React版本。2021，我会这样写这个组件：

import React, { useState } from "react";
import "./DropDown.css";

export function DropDown({ options, callback }) {
    const [selected, setSelected] = useState("");
    const [expanded, setExpanded] = useState(false);

    function expand() {
        setExpanded(true);
    }

    function close() {
        setExpanded(false);
    }

    function select(event) {
        const value = event.target.textContent;
        callback(value);
        close();
        setSelected(value);
    }

    return (
        <div className="dropdown" tabIndex={0} onFocus={expand} onBlur={close} >
            <div>{selected}</div>
            {expanded ? (
                <div className={"dropdown-options-list"}>
                    {options.map((O) => (
                        <div className={"dropdown-option"} onClick={select}>
                            {O}
                        </div>
                    ))}
                </div>
            ) : null}
        </div>
    );
}

原始答案（2016）：

以下是最适合我的解决方案，无需将事件附加到容器：

某些HTML元素可以具有所谓的“焦点”，例如输入元素。当这些元素失去焦点时，它们也会对模糊事件做出响应。

要使任何元素具有焦点的能力，只需确保其tabindex属性设置为-1以外的任何值。在常规HTML中，这是通过设置tabindex属性实现的，但在React中，必须使用tabindex（注意大写I）。

您也可以通过JavaScript使用element.setAttribute（'tabindex'，0）执行此操作

这就是我用来制作自定义下拉菜单的原因。

var DropDownMenu = React.createClass({
    getInitialState: function(){
        return {
            expanded: false
        }
    },
    expand: function(){
        this.setState({expanded: true});
    },
    collapse: function(){
        this.setState({expanded: false});
    },
    render: function(){
        if(this.state.expanded){
            var dropdown = ...; //the dropdown content
        } else {
            var dropdown = undefined;
        }
        
        return (
            <div className="dropDownMenu" tabIndex="0" onBlur={ this.collapse } >
                <div className="currentValue" onClick={this.expand}>
                    {this.props.displayValue}
                </div>
                {dropdown}
            </div>
        );
    }
});

这是我的方法（演示-https://jsfiddle.net/agymay93/4/):

我创建了一个名为WatchClickOutside的特殊组件，它可以像这样使用（我假设JSX语法）：

<WatchClickOutside onClickOutside={this.handleClose}>
  <SomeDropdownEtc>
</WatchClickOutside>

以下是WatchClickOutside组件的代码：

import React, { Component } from 'react';

export default class WatchClickOutside extends Component {
  constructor(props) {
    super(props);
    this.handleClick = this.handleClick.bind(this);
  }

  componentWillMount() {
    document.body.addEventListener('click', this.handleClick);
  }

  componentWillUnmount() {
    // remember to remove all events to avoid memory leaks
    document.body.removeEventListener('click', this.handleClick);
  }

  handleClick(event) {
    const {container} = this.refs; // get container that we'll wait to be clicked outside
    const {onClickOutside} = this.props; // get click outside callback
    const {target} = event; // get direct click event target

    // if there is no proper callback - no point of checking
    if (typeof onClickOutside !== 'function') {
      return;
    }

    // if target is container - container was not clicked outside
    // if container contains clicked target - click was not outside of it
    if (target !== container && !container.contains(target)) {
      onClickOutside(event); // clicked outside - fire callback
    }
  }

  render() {
    return (
      <div ref="container">
        {this.props.children}
      </div>
    );
  }
}

如果您需要typescript版本：

import React, { useRef, useEffect } from "react";

interface Props {
  ref: React.MutableRefObject<any>;

}

export const useOutsideAlerter = ({ ref }: Props) => {
  useEffect(() => {
    const handleClickOutside = (event: MouseEvent) => {
      if (ref.current && !ref.current.contains(event.target as Node)) {
       //do what ever you want
      }
    };
    // Bind the event listener
    document.addEventListener("mousedown", handleClickOutside);
    return () => {
      // Unbind the event listener on clean up
      document.removeEventListener("mousedown", handleClickOutside);
    };
  }, [ref]);
};
export default useOutsideAlerter;

如果您想扩展它以关闭模态或隐藏某些内容，也可以执行以下操作：

import React, { useRef, useEffect } from "react";

interface Props {
  ref: React.MutableRefObject<any>;
  setter: React.Dispatch<React.SetStateAction<boolean>>;
}

export const useOutsideAlerter = ({ ref, setter }: Props) => {
  useEffect(() => {
    const handleClickOutside = (event: MouseEvent) => {
      if (ref.current && !ref.current.contains(event.target as Node)) {
        setter(false);
      }
    };
    // Bind the event listener
    document.addEventListener("mousedown", handleClickOutside);
    return () => {
      // Unbind the event listener on clean up
      document.removeEventListener("mousedown", handleClickOutside);
    };
  }, [ref, setter]);
};
export default useOutsideAlerter;

为了扩展Ben Bud给出的公认答案，如果您使用的是样式化组件，那么这样传递引用会给您一个错误，例如“this.wrapperRef.contains is not a function”。

在注释中，建议的修复方法是用div包装样式化的组件，并将ref传递到那里。尽管如此，在他们的文档中，他们已经解释了这一点的原因，以及在样式化组件中正确使用ref：

将ref属性传递给样式化组件将为您提供StyledComponent包装器的实例，但不会传递给底层DOM节点。这是由于裁判的工作方式。不可能直接在包装器上调用DOM方法，如focus。要获取对实际包装的DOM节点的引用，请将回调传递给innerRef属性。

像这样：

<StyledDiv innerRef={el => { this.el = el }} />

然后您可以在“handleClickOutside”函数中直接访问它：

handleClickOutside = e => {
    if (this.el && !this.el.contains(e.target)) {
        console.log('clicked outside')
    }
}

这也适用于“onBlur”方法：

componentDidMount(){
    this.el.focus()
}
blurHandler = () => {
    console.log('clicked outside')
}
render(){
    return(
        <StyledDiv
            onBlur={this.blurHandler}
            tabIndex="0"
            innerRef={el => { this.el = el }}
        />
    )
}

Ez的方式。。。（2022年更新）

创建挂钩：useOutsideClick.ts

export function useOutsideClick(ref: any, onClickOut: () => void){
    useEffect(() => {
        const onClick = ({target}: any) => !ref.contains(target) && onClickOut?.()
        document.addEventListener("click", onClick);
        return () => document.removeEventListener("click", onClick);
    }, []);
}

将componentRef添加到组件并调用useOutsideClick

export function Example(){

  const componentRef = useRef();

  useOutsideClick(componentRef.current!, () => {
   // do something here
  });

  return ( 
    <div ref={componentRef as any}> My Component </div>
  )
}

或者：

const onClickOutsideListener = () => {
    alert("click outside")
    document.removeEventListener("click", onClickOutsideListener)
  }

...

return (
  <div
    onMouseLeave={() => {
          document.addEventListener("click", onClickOutsideListener)
        }}
  >
   ...
  </div>