缺少这一行path：
<Route name="ideas" handler={CreateIdeaView} />
应该：
<Route name="ideas" path="/:testvalue" handler={CreateIdeaView} />
鉴于以下Link （过时的 v1）：
<Link to="ideas" params={{ testvalue: "hello" }}>Create Idea</Link>
最新的 v4/v5：
const backUrl = '/some/other/value'
// this.props.testvalue === "hello"
// Using query
<Link to={{pathname: `/${this.props.testvalue}`, query: {backUrl}}} />
// Using search
<Link to={{pathname: `/${this.props.testvalue}`, search: `?backUrl=${backUrl}`} />
<Link to={`/${this.props.testvalue}?backUrl=${backUrl}`} />
在withRouter(CreateIdeaView)组件中render()，withRouter高阶组件的过时用法：
console.log(this.props.match.params.testvalue, this.props.location.query.backurl)
// output
hello /some/other/value
在使用useParams和useLocation钩子的功能组件中：
const CreatedIdeaView = () => {
const { testvalue } = useParams();
const { query, search } = useLocation();
console.log(testvalue, query.backUrl, new URLSearchParams(search).get('backUrl'))
return <span>{testvalue} {backurl}</span>
}
从您在文档上发布的链接到页面底部：
给定一条路线 <Route name="user" path="/users/:userId"/>
使用一些存根查询示例更新了代码示例：
// import React, {Component, Props, ReactDOM} from 'react';
// import {Route, Switch} from 'react-router'; etc etc
// this snippet has it all attached to window since its in browser
const {
BrowserRouter,
Switch,
Route,
Link,
NavLink
} = ReactRouterDOM;
class World extends React.Component {
constructor(props) {
super(props);
console.dir(props);
this.state = {
fromIdeas: props.match.params.WORLD || 'unknown'
}
}
render() {
const { match, location} = this.props;
return (
<React.Fragment>
<h2>{this.state.fromIdeas}</h2>
<span>thing:
{location.query
&& location.query.thing}
</span><br/>
<span>another1:
{location.query
&& location.query.another1
|| 'none for 2 or 3'}
</span>
</React.Fragment>
);
}
}
class Ideas extends React.Component {
constructor(props) {
super(props);
console.dir(props);
this.state = {
fromAppItem: props.location.item,
fromAppId: props.location.id,
nextPage: 'world1',
showWorld2: false
}
}
render() {
return (
<React.Fragment>
<li>item: {this.state.fromAppItem.okay}</li>
<li>id: {this.state.fromAppId}</li>
<li>
<Link
to={{
pathname: `/hello/${this.state.nextPage}`,
query:{thing: 'asdf', another1: 'stuff'}
}}>
Home 1
</Link>
</li>
<li>
<button
onClick={() => this.setState({
nextPage: 'world2',
showWorld2: true})}>
switch 2
</button>
</li>
{this.state.showWorld2
&&
<li>
<Link
to={{
pathname: `/hello/${this.state.nextPage}`,
query:{thing: 'fdsa'}}} >
Home 2
</Link>
</li>
}
<NavLink to="/hello">Home 3</NavLink>
</React.Fragment>
);
}
}
class App extends React.Component {
render() {
return (
<React.Fragment>
<Link to={{
pathname:'/ideas/:id',
id: 222,
item: {
okay: 123
}}}>Ideas</Link>
<Switch>
<Route exact path='/ideas/:id/' component={Ideas}/>
<Route path='/hello/:WORLD?/:thing?' component={World}/>
</Switch>
</React.Fragment>
);
}
}
ReactDOM.render((
<BrowserRouter>
<App />
</BrowserRouter>
), document.getElementById('ideas'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-router-dom/4.3.1/react-router-dom.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-router/4.3.1/react-router.min.js"></script>
<div id="ideas"></div>
＃更新：
参见：https : //github.com/ReactTraining/react-router/blob/0c6d51cd6639aff8a84b11d89e27887b3558ed8a/upgrade-guides/v2.0.0.md#link-to-onenter-and-isactive-use-location-descriptors
从 1.x 到 2.x 的升级指南：
<Link to>、 onEnter 和 isActive 使用位置描述符
<Link to>除了字符串之外，现在还可以使用位置描述符。不推荐使用查询和状态props。
// v1.0.x
<Link to="/foo" query={{ the: 'query' }}/>
// v2.0.0
<Link to={{ pathname: '/foo', query: { the: 'query' } }}/>
// 在 2.x 中仍然有效
<Link to="/foo"/>
同样，从 onEnter 钩子重定向现在也使用位置描述符。
// v1.0.x
(nextState, replaceState) => replaceState(null, '/foo')
(nextState, replaceState) => replaceState(null, '/foo', { the: 'query' })
// v2.0.0
(nextState, replace) => replace('/foo')
(nextState, replace) => replace({ pathname: '/foo', query: { the: 'query' } })
对于自定义类似链接的组件，同样适用于 router.isActive，之前的 history.isActive。
// v1.0.x
history.isActive(pathname, query, indexOnly)
// v2.0.0
router.isActive({ pathname, query }, indexOnly)
#v3 到 v4 的更新：
界面基本上还是和v2一样，最好看react-router的CHANGES.md，因为那里是更新的地方。
子孙后代的“遗留移民文件”