Reactjs 从父组件状态填充无状态子组件道具,以显示React中嵌套的无序列表(使用Firebase)
我可能在这里遗漏了一些非常简单的东西,但我无法让我的代码正常运行。我试图为每个Reactjs 从父组件状态填充无状态子组件道具,以显示React中嵌套的无序列表(使用Firebase),reactjs,state,react-props,Reactjs,State,React Props,我可能在这里遗漏了一些非常简单的东西,但我无法让我的代码正常运行。我试图为每个referenceList显示一个嵌套的无序列表referenceList。我想主要的问题是如何将状态变量referenceListItems传递到子组件referenceListItems const ReferencePage = () => ( <div> <h1>Reference</h1> <Reference /> </di
referenceList
显示一个嵌套的无序列表referenceList
。我想主要的问题是如何将状态变量referenceListItems
传递到子组件referenceListItems
const ReferencePage = () => (
<div>
<h1>Reference</h1>
<Reference />
</div>
);
class ReferenceBase extends Component {
constructor(props) {
super(props);
this.state = {
loading: false,
referenceLists: [],
referenceListItems: [],
};
}
componentDidMount() {
this.onListenForReferenceLists();
this.onListenForReferenceListItems();
}
onListenForReferenceLists() {
this.setState({ loading: true });
this.unsubscribeReferenceLists = this.props.firebase
.referenceLists()
.onSnapshot(snapshot => {
if (snapshot.size) {
let referenceLists = [];
snapshot.forEach(doc =>
referenceLists.push({ ...doc.data(), uid: doc.id }),
);
this.setState({
referenceLists: referenceLists,
loading: false
});
} else {
this.setState({ referenceLists: null, loading: false });
}
});
}
onListenForReferenceListItems() {
this.unsubscribeReferenceListsItems = this.props.firebase
.referenceListItems()
.onSnapshot(snapshot => {
if (snapshot.size) {
let referenceListItems = [];
snapshot.forEach(doc =>
referenceListItems.push({ ...doc.data(), uid: doc.id }),
);
this.setState({
referenceListItems: referenceListItems,
loading: false
});
} else {
this.setState({ referenceListItems: null, loading: false });
}
});
}
componentWillUnmount() {
this.unsubscribeReferenceLists();
this.unsubscribeReferenceListsItems();
}
render() {
const { referenceLists, referenceListItems, loading } = this.state;
return (
<div>
{loading && <div>Loading ...</div>}
{referenceLists ? (
<ReferenceLists referenceLists={referenceLists} />
):(
<div>There are no reference items ...</div>
)}
</div>
);
}
}
const Reference = withFirebase(ReferenceBase);
const ReferenceLists = ({ referenceLists }) => (
<ul className="reference-lists">
{referenceLists.map( referenceList => (
<ReferenceList key={referenceList.uid} referenceList={referenceList} />
))}
</ul>
);
const ReferenceList = ({ referenceList }) => (
<li className="reference">
<strong>{referenceList.userId}</strong> {referenceList.name}
<ReferenceListItems />
</li>
);
const ReferenceListItems =({ referenceListItems }) => (
<ul className="reference-list-items">
{referenceListItems.map( referenceListItem => (
<ReferenceListItem key={referenceListItem.uid} referenceListItem={referenceListItem} />
))}
</ul>
);
const ReferenceListItem = ({ referenceListItem }) => (
<li className="reference-list-item">
<strong>{referenceListItem.userId}</strong> {referenceListItem.name}
</li>
);
const ReferencePage=()=>(
参考
);
类ReferenceBase扩展组件{
建造师(道具){
超级(道具);
此.state={
加载:false,
推荐人:[],
参考列表项:[],
};
}
componentDidMount(){
this.onListenforReferenceList();
this.onListenForReferenceListItems();
}
onListenforReferenceList(){
this.setState({loading:true});
this.unsubscribeReferenceLists=this.props.firebase
.referenceLists()
.onSnapshot(快照=>{
if(snapshot.size){
让引用者=[];
snapshot.forEach(doc=>
push({…doc.data(),uid:doc.id}),
);
这是我的国家({
参考者:参考者,
加载:错误
});
}否则{
this.setState({referenceLists:null,load:false});
}
});
}
onListenForReferenceListItems(){
this.unsubscribeReferenceListsItems=this.props.firebase
.referenceListItems()
.onSnapshot(快照=>{
if(snapshot.size){
让referenceListItems=[];
snapshot.forEach(doc=>
referenceListItems.push({…doc.data(),uid:doc.id}),
);
这是我的国家({
referenceListItems:referenceListItems,
加载:错误
});
}否则{
this.setState({referenceListItems:null,load:false});
}
});
}
组件将卸载(){
此。取消订阅引用列表();
此。取消订阅ReferenceListSites();
}
render(){
const{referenceLists,referencelistems,load}=this.state;
返回(
{正在加载和正在加载…}
{公投者(
):(
没有参考项目。。。
)}
);
}
}
const Reference=withFirebase(ReferenceBase);
const ReferenceLists=({ReferenceLists})=>(
{referenceList.map(referenceList=>(
))}
);
const ReferenceList=({ReferenceList})=>(
{referenceList.userId}{referenceList.name}
);
常量ReferenceListItems=({ReferenceListItems})=>(
{referenceListItems.map(referenceListItem=>(
))}
);
常量ReferenceListItem=({ReferenceListItem})=>(
{referenceListItem.userId}{referenceListItem.name}
);
通过重新定义引用列表
let referenceLists = [];
在你的课堂上从来没有设置过。您需要在闭包内返回referencelist,或者在回调中设置类级别变量
this.referenceLists.push({ ...doc.data(), uid: doc.id })
您没有在父
ReferenceBase
组件中显式使用ReferenceListItems
。因此,您只需将其作为属性传递到整个组件树中
render() {
const { referenceLists, referenceListItems, loading } = this.state;
return (
<div>
{loading && <div>Loading ...</div>}
{referenceLists ? (
<ReferenceLists referenceLists={referenceLists} referenceListItems={referenceListItems} />
):(
<div>There are no reference items ...</div>
)}
</div>
);
render(){
const{referenceLists,referencelistems,load}=this.state;
返回(
{正在加载和正在加载…}
{公投者(
):(
没有参考项目。。。
)}
);
公投者
constreferencelists=({ReferenceLists,referencelistems})=>(
{referenceList.map(referenceList=>(
))}
参考者
const ReferenceList=({ReferenceList,ReferenceList})=>(
{referenceList.userId}{referenceList.name}
);
ReferenceListItems是在另一个文件中定义的吗?不,我想避免为它创建另一个类,因为它只是一个非常简单的显示。它现在是一个无状态组件。它确实在渲染调用中设置(如果这是您的意思的话).我在显示参考列表时没有问题,只显示子项。对不起,我的错误我认为是您正在寻找的汉克斯!您建议这种方法吗?(看起来有点乏味)您可以交换组件的参数以使您的答案看起来不同。我看不出您的答案与您之前的答案有什么不同。@Pim。非常欢迎您!看看您设置这些组件的方式,我认为这是最容易实现的解决方案。您还可以查看React.Context api:。这允许您将道具从HOC传递到嵌套较深的子组件,而无需繁琐地传递。但是,这将迫使您重新考虑组件树。@Pim啊,我明白了。我认为ReferenceListItems最终需要管理自己的状态等。可能需要将其作为类组件。在任何情况下,pa向它传递道具应该是相同的。@Pim也不要将数据作为道具向下传递,使用redux它很容易实现
const ReferenceLists = ({ referenceLists, referenceListItems }) => (
<ul className="reference-lists">
{referenceLists.map( referenceList => (
<ReferenceList key={referenceList.uid} referenceList={referenceList} referenceListItems={referenceListItems} />
))}
</ul>
const ReferenceList = ({ referenceList, referenceListItems }) => (
<li className="reference">
<strong>{referenceList.userId}</strong> {referenceList.name}
<ReferenceListItems referenceListItems={referenceListItems}/>
</li>
);