state-management 相关问题

无法克隆 GitHub 存储库

D： setau-management λ git config --global --unset http.proxy d: 设置管理 λ git clone https://github.com/aramali0/restaurant-management-system.git 克隆进入“餐厅管理系统...

Microsoft SQL Server Management Studio - 查询结果为文本

我在 Microsoft SQL Server 中有一个数据库，并且正在使用 Microsoft SQL Server Management Studio。我可以选择将查询结果插入到文件中，尽管查询结果不是

spring依赖管理gradle插件依赖版本jars

可以通过两种方式导入依赖管理。插件{ id 'io.spring.dependency-management' 版本 '1.1.4' } 依赖项{ 实现平台("org.springframework.boot:spring-boot-

需要创建类变量，它是该类的子类，如何管理引用

请考虑以下代码作为问题的示例。班级状态： START: State = StartState() # 问题在这里 - StartState END: State = EndState() # 问题在这里 - EndStat...

React-Redux useSelector typescript type for state

我正在使用 React-Redux 中的 useSelector(state => state.SLICE_NAME) 挂钩，但是我在定义状态参数时遇到了困难。它默认设置为未知，因此当我尝试时会收到错误...

SQL Server Management Studio 和 Razor 页面

大家好，我正在学习微软官方网站提供的 Razor Pages 教程。该教程指导我构建一个管理电影数据库的网络应用程序 https://learn。

与 AsyncImage iOS 15 匹配的几何效果

考虑以下示例：结构ContentView：视图{ @State var showSplash: Bool = true @Namespace var 动画命名空间 var body: 一些视图 { ZStack { 如果

Powershell 如何在 Try Catch 块中处理 Az Cli

我有以下代码...... 当找不到资源时，会引发错误，但代码继续运行...不知道为什么？尝试{ $state=$(az synapse sql 池显示 --n...

Verilog 状态机状态/next_state 风格

我是一名 Verilog 初学者，我正在尝试了解在常见 FPGA 平台上实现 FSM 的最佳方法。我看过很多鼓励 state/next_state 的论文（例如这篇）......

Rive 动画加载时间过长，出现 RangeError（索引）：无效值：有效值范围为空：0

创建一个空项目并使用以下命令加载以下文件 all_animations.riv 代码：类 _MyHomePageState 扩展 State { 画板？ _riveArtBoard；状态机控制器？

State<WelcomePage>createState() => _WelcomePageState(); }

我对编码/flutter/dart很陌生，我试图在前进的过程中拾取东西。我正在尝试为应用程序构建欢迎页面。一切都很顺利，直到我尝试向显示密码字段添加功能......

如何在具有预定义值的表单输入上使用State？

我想要一个带有默认值的表单，并且用户输入的任何值都会被捕获。这是我的代码：从“preact/hooks”导入{useState}；导出默认函数 test() { 合作...

当我尝试向 Postgres 中的现有表添加约束时，为什么会收到 SQL state:23503？

我有一个特殊的 User 表 Advisor，仅包含 id 和 user_id （目前！），我尝试使用以下脚本将 user_id 设为外键：更改表顾问添加约束

如何更改可编辑列表中重新排序图标的颜色？

我有一个可编辑的列表，其中可以重新订购哪些商品。我想更改重新排序颜色。怎么做？结构虚拟列表：查看{ @State private var items = ["项目 1", "项目 2&

MatToolbar：尝试组合不同的工具栏模式

出现以下错误： MatToolbar：尝试组合不同的工具栏模式。显式指定多个元素或仅将内容放置在中出现以下错误： MatToolbar：尝试组合不同的工具栏模式。要么显式指定多个 <mat-toolbar-row> 元素，要么仅将内容放置在单行的 <mat-toolbar> 中。我的代码已经在 mat-toolbar 中应用了 mat-toolbar-row。然而，该错误仍然存在。 html文件的代码片段如下： <div class="wallpaper"> <mat-toolbar color="primary"> <mat-toolbar-row> <span>Welcome, User</span> <span class="example-fill-remaining-space"></span> <span class="align-center"></span> <span class="example-spacer"></span> <button mat-button>Create Incident </button> <a [routerLink]="['/closed']"><button mat-button style="color: white">Closed Incident</button></a> <span class="example-spacer"></span> <a [routerLink]="['/login']"><button mat-button>Logout</button></a> <img src="../../assets/hsbc_logo3.png" class="logo-hsbc"/> </mat-toolbar-row> <h1>INCIDENT MANAGEMENT SYSTEM</h1> </mat-toolbar> <h1>Welcome to Incident Management System</h1> <mat-card style="background: transparent">  <mat-card-title>Incident Details</mat-card-title> <mat-card-content> <form> <table > <tr> <td> <mat-form-field class="demo-full-width"> <mat-label >Description</mat-label> <textarea [(ngModel)]="incident.description" name="description" cdkTextareaAutosize cdkAutosizeMinRows="1" cdkAutosizeMaxRows="5" matInput></textarea> </mat-form-field> </td> <td> <h4>{{message}}</h4> </td> </tr> <tr> <td> <mat-form-field class="demo-full-width"> <input matInput [matDatepicker]="picker" placeholder="Incident Date" [(ngModel)]="incident.date" name="date" > <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle> <mat-datepicker touchUi="true" #picker></mat-datepicker> </mat-form-field> </td> </tr> <tr> <td colspan="2"> <mat-form-field class="demo-full-width"> <input matInput placeholder="Incident Category" [(ngModel)]="incident.category" name="category"> </mat-form-field> </td> </tr> <tr> <td > <mat-form-field class="demo-full-width"> <mat-select placeholder="Application Owner" [(ngModel)]="incident.owner" name="owner"> <mat-option style="background-color:grey">-- Select--</mat-option> <mat-option style="background-color:cornsilk" value="1">BRV</mat-option> <mat-option style="background-color:cornsilk" value="2">FRTB</mat-option> <mat-option style="background-color:cornsilk" value="3">FSA</mat-option> </mat-select> </mat-form-field> </td> <td> <mat-form-field> <mat-select placeholder="Symphony Group" [(ngModel)]="incident.symphony_group" name="symphony_group"> <mat-option style="background-color:grey">-- Select --</mat-option> <mat-option style="background-color:cornsilk" value="1">MMO SheHacks</mat-option> <mat-option style="background-color: cornsilk" value="2">MMO IT INDIA</mat-option> </mat-select> </mat-form-field> </td> </tr> <tr> <td> <mat-form-field> <mat-select placeholder="Application" [(ngModel)]="incident.application" name="application"> <mat-option style="background-color:grey">-- Select--</mat-option> <mat-option style="background-color:cornsilk" value="1">BRV</mat-option> <mat-option style="background-color:cornsilk" value="2">FRTB</mat-option> <mat-option style="background-color:cornsilk" value="3">FSA</mat-option> </mat-select> </mat-form-field> </td> <td> <mat-form-field> <mat-select placeholder="Status" [(value)]="status" [(ngModel)]="incident.status" name="status"> <mat-option style="background-color:grey">-- Select --</mat-option> <mat-option style="background-color: green" value="1">Available</mat-option> <mat-option style="background-color: orange" value="2">Reduced</mat-option> <mat-option style="background-color: red" value="3">Unavailable</mat-option> </mat-select> </mat-form-field> </td> </tr> <tr> <td colspan="2"> </td> </tr> <tr> <td colspan="2" class="content-center"> <button style="margin:5px" mat-raised-button color="accent" (click)="submit()">Submit Incident</button> <button style="margin:5px" mat-raised-button color="accent" (click)="reset()">Clear</button> <button style="margin:5px" mat-raised-button color="accent">Raise BGCR</button> <button style="margin:5px" mat-raised-button color="accent">Raise Jira</button> </td> </tr> </table> </form> </mat-card-content> </mat-card> </div> 您需要移除 <h1>INCIDENT MANAGEMENT SYSTEM</h1> 或将其放入 <mat-toolbar-row> 内。我无法在垫子工具栏中填充图像有什么帮助吗？

ASP.NET MVC 项目模板在移动设备上无法调整为 100%

我不明白为什么 Web .Net MVC 项目上的默认模板没有在移动设备中调整为 100% 宽度。我在视图上使用数据表： @模型IEnumerable 我不明白为什么 Web .Net MVC 项目上的默认模板没有在移动设备中调整为 100% 宽度。我在视图上使用数据表： @model IEnumerable<iziConference.Models.EventAttendee> <h2>Participantes.</h2> <br /> <button><a style="text-decoration: none" href='@Url.Action("Create", new { eventId = ViewBag.EventId })'>Criar Participante</a></button> <button id="at-btn-refresh"> Actualizar</button> <input id="eventId" type="hidden" value="@ViewBag.EventId"> <table id="at-attendees-list" cellpadding="10" border="1" class="row-border stripe"> <thead> <tr> <th>ID</th> <th>Tipo</th> <th>Nome</th> <th>Email</th> <th>Estado </th> </tr> </thead> <tbody> @foreach (var item in Model) { <tr id="[email protected]_Id"> <td style="padding: 5px"> @Html.DisplayFor(modelItem => item.Attendee.Id) </td> <td> @Html.DisplayFor(modelItem => item.AttendeeType) </td> <td> @Html.DisplayFor(modelItem => item.Attendee.Name) </td> <td> @Html.DisplayFor(modelItem => item.Attendee.Email) </td> <td> @if (item.IsActive) { <button id="[email protected]_Id" class="at-btn-active-state active" data-attendee-id="@item.Attendee_Id" data-attendee-name="@item.Attendee.Name" data-active-new-state="false" data-show-confirmation-alert="true">Desactivar</button> } else { <button id="[email protected]_Id" class="at-btn-active-state inactive" data-attendee-id="@item.Attendee_Id" data-attendee-name="@item.Attendee.Name" data-active-new-state="true" data-show-confirmation-alert="true">Activar</button> } </td> </tr> } </tbody> </table> 由脚本加载： var _atteendeesList = "at-attendees-list"; $("#" + _atteendeesList).DataTable({ "paging": false, "info": false, "language": { "search": "Pesquisar:", "info": "Participantes inscritos: _PAGES_" } }); 使用默认的_Layout.cshtml： <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>izigo Conference - Gestor de Conteúdos</title> <link href="~/favicon.ico" rel="shortcut icon" type="image/x-icon" /> <meta name="viewport" content="width=device-width" /> @Styles.Render("~/Content/css") @Scripts.Render("~/bundles/modernizr") </head> <body> <header> <div class="content-wrapper"> <section id="login"> @Html.Partial(MVC.Account.Views._LoginPartial) </section> <div style="padding: 10px;"> @if (Request.IsAuthenticated) { <nav> <ul id="menu"> <li>@Html.ActionLink("Home", MVC.Home.Index())</li> <li>@Html.ActionLink("Participantes", MVC.Attendee.Index())</li> <li>@Html.ActionLink("Check-in", MVC.Checkin.Index())</li> </ul> </nav> } </div> </div> </header> <div id="body"> @RenderSection("featured", required: false) <section class="content-wrapper main-content clear-fix"> @RenderBody() </section> </div> <footer style="padding-left: 25px;"> <div class="content-wrapper"> <div class="float-left"> <p>© @DateTime.Now.Year - <a href="https://www.izigo.pt/conference" target="_blank">izigo Conference</a> - <i>Powered by</i><a href="https://www.izigo.pt" target="_blank">izigo.pt</a></p> </div> </div> </footer> @Scripts.Render("~/bundles/jquery", "~/bundles/iziconference") @RenderSection("scripts", required: false) </body> </html> 研究了 dataTables 库的选项后，我找到了一个创建响应式解决方案的选项：我已经包含了响应表结构和columnDefs的选项，以选择哪些选项在移动设备中保持可见： $("#" + _atteendeesList).DataTable({ "responsive": true, "columnDefs": [ { responsivePriority: 1, targets: 0 }, { responsivePriority: 2, targets: -1 } ], "paging": false, "info": false, "language": { "search": "Pesquisar:", "info": "Participantes inscritos: _PAGES_" } }); 我还必须在捆绑包中包含数据表扩展的 js 和 css 响应式库（可在此处下载：https://datatables.net/download/）： bundles.Add(new ScriptBundle("~/bundles/iziconference").Include( "~/Content/Scripts/datatables.min.js", "~/Content/Scripts/dataTables.responsive.min.js")); // add-on bundles.Add(new StyleBundle("~/Content/css").Include( "~/Content/Styles/datatables.min.css", "~/Content/Styles/responsive.dataTables.min.css"));

android中customView中如何收集Viewmodel StateFlow

android中customView中如何采集StateFlow 我有一个视图模型类 MyViewModel : ViewModel() { 私有 val _myState = MutableStateFlow(MyState()) val myState：StateFlow android中customView中如何采集StateFlow 我有一个视图模型 class MyViewModel : ViewModel() { private val _myState = MutableStateFlow(MyState()) val myState: StateFlow<MyState> = _myState fun updateMyState(newState: MyState) { _myState.value = newState } } data class MyState( val name: String = "", val age: Int = 0, val isMarried: Boolean = false ) 我能够使用收集活动中的更新数据 lifecycleScope.launchWhenStarted { viewModel.myState.collect { state -> Log.e("collected ", "tateflow: ${state.name}") } } 我们如何根据收集的数据更新自定义视图？我们如何根据这些数据更新自定义视图您能分享一下在自定义视图中创建 viewModel 的代码吗？你的代码是不是类似这样： private val viewModel: ActivityViewModel by activityViewModels()

如何在webview中加载html字符串？

我有一个包含以下内容的html字符串：我有一个包含以下内容的html字符串： <!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=windows-1250"> <meta name="spanish press" content="spain, spanish newspaper, news,economy,politics,sports"> <title></title> </head> <body id="body">  <script src="http://www.myscript.com/a"></script> </body> </html> 我需要将该网站显示到 Android 中的网络视图中。我尝试过这一切： webView.loadDataWithBaseURL(null, txt, "text/html", "UTF-8", null); webView.loadDataWithBaseURL("x-data://base", txt, "text/html", "UTF-8", null); webView.loadDataWithBaseURL("notreal/", txt, "text/htm", "utf-8",null); 我还尝试删除 DOCTYPE 标签： txt=txt.replace("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">", ""); 这些人都没有工作。我刚刚实现了将字符串显示到 webview（html 代码）中，但不是必须使用该 html 代码创建的网站。出了什么问题？在 WebView 中加载数据。调用WebView的loadData()方法 wv.loadData(yourData, "text/html", "UTF-8"); 你可以查看这个例子 http://developer.android.com/reference/android/webkit/WebView.html [编辑1] 您应该在 -- " 之前添加 -- \ -- 例如 --> name=\"spanish press\" 下面的字符串对我有用 String webData = "<!DOCTYPE html><head> <meta http-equiv=\"Content-Type\" " + "content=\"text/html; charset=utf-8\"> <html><head><meta http-equiv=\"content-type\" content=\"text/html; charset=windows-1250\">"+ "<meta name=\"spanish press\" content=\"spain, spanish newspaper, news,economy,politics,sports\"><title></title></head><body id=\"body\">"+ "<script src=\"http://www.myscript.com/a\"></script>şlkasşldkasşdksaşdkaşskdşk</body></html>"; 你也可以试试这个 final WebView webView = new WebView(this); webView.loadDataWithBaseURL(null, content, "text/html", "UTF-8", null); 从资产 html 文件中读取 ViewGroup webGroup; String content = readContent("content/ganji.html"); final WebView webView = new WebView(this); webView.loadDataWithBaseURL(null, content, "text/html", "UTF-8", null); webGroup.addView(webView); 我有同样的要求，我是按照以下方式完成的。你也可以试试这个。使用loadData方法 web.loadData(""" <p style='text-align:center'> <img class='aligncenter size-full wp-image-1607' title='' src="+movImage+" alt='' width='240px' height='180px' /> </p> <p> <center> <U> <H2>"+movName+"("+movYear+")</H2> </U> </center> </p> <p><strong>Director : </strong>"+movDirector+"</p> <p><strong>Producer : </strong>"+movProducer+"</p> <p><strong>Character : </strong>"+movActedAs+"</p> <p><strong>Summary : </strong>"+movAnecdotes+"</p> <p><strong>Synopsis : </strong>"+movSynopsis+"</p> """, "text/html", "UTF-8" ); movDirector movProducer 都是我的字符串变量。简而言之，我保留了 URL 的自定义样式。如果您正在 JetpackCompose 中寻找某些内容，这可以帮助您： @Composable fun HtmlTextVisualizerComponent(textFromData: String) { val mimeType = "text/html" val encoding = "UTF-8" LazyColumn( modifier = Modifier .padding( start = 24.dp, end = 24.dp, top = 16.dp, bottom = 24.dp, ), ) { items(1) { val state = rememberWebViewState( url = "data:$mimeType;$encoding,$textFromData", ) val navigator = rememberWebViewNavigator() WebView( state = state, modifier = Modifier.fillMaxSize(), navigator = navigator, onCreated = { it.settings.javaScriptEnabled = true }, ) } } } 一定不要忘记在你的 gradle 中添加依赖项： implementation "com.google.accompanist:accompanist-webview:0.30.1"

嵌套 useFetch 导致 Nuxt 3 中的 Hydration 节点不匹配

在 Nuxt 3 页面内，我通过从 pinia 存储调用操作来获取帖子数据： {{ 发布数据 }} {{ 帖子内容... 在 Nuxt 3 页面内，我通过从 pinia 商店调用操作来获取帖子数据： <template> <div v-if="postData && postContent"> {{ postData }} {{ postContent }} </div> </template> <script setup> const config = useRuntimeConfig() const route = useRoute() const slug = route.params.slug const url = config.public.wpApiUrl const contentStore = useContentStore() await contentStore.fetchPostData({ url, slug }) const postData = contentStore.postData const postContent = contentStore.postContent </script> 那是我的商店： import { defineStore } from 'pinia' export const useContentStore = defineStore('content',{ state: () => ({ postData: null, postContent: null }), actions: { async fetchPostData({ url, slug }) { try { const { data: postData, error } = await useFetch(`${url}/wp/v2/posts`, { query: { slug: slug }, transform(data) { return data.map((post) => ({ id: post.id, title: post.title.rendered, content: post.content.rendered, excerpt: post.excerpt.rendered, date: post.date, slug: post.slug, })); } }) this.postData = postData.value; if (postData && postData.value && postData.value.length && postData.value[0].id) { const {data: postContent} = await useFetch(`${url}/rl/v1/get?id=${postData.value[0].id}`, { method: 'POST', }); this.postContent = postContent.value; } } catch (error) { console.error('Error fetching post data:', error) } } } }); 浏览器中的输出正常，但我在浏览器控制台中收到以下错误： entry.js:54 [Vue warn]: Hydration node mismatch: - rendered on server:  - expected on client: div at <[slug] onVnodeUnmounted=fn<onVnodeUnmounted> ref=Ref< undefined > > at <Anonymous key="/news/hello-world()" vnode= {__v_isVNode: true, __v_skip: true, type: {…}, props: {…}, key: null, …} route= {fullPath: '/news/hello-world', hash: '', query: {…}, name: 'news-slug', path: '/news/hello-world', …} ... > at <RouterView name=undefined route=undefined > at <NuxtPage> at <Default ref=Ref< undefined > > at <LayoutLoader key="default" layoutProps= {ref: RefImpl} name="default" > at <NuxtLayoutProvider layoutProps= {ref: RefImpl} key="default" name="default" ... > at <NuxtLayout> at <App key=3 > at <NuxtRoot> 如何解决这个问题？我尝试在 onMounted 中获取帖子数据，但在这种情况下 postData 和 postContent 保持为空 onMounted(async () => { await contentStore.fetchPostData({ url, slug }) }) 您可以使用 ClientOnly 组件来消除该警告。请参阅文档了解更多信息。该组件仅在客户端渲染其插槽。

Vue 3如何获取$children的信息

这是我在 Tabs 组件中使用 VUE 2 的旧代码：创建（）{ this.tabs = this.$children; } 标签： .... 这是我在 Tabs 组件中使用 VUE 2 的旧代码： created() { this.tabs = this.$children; } 标签： <Tabs> <Tab title="tab title"> .... </Tab> <Tab title="tab title"> .... </Tab> </Tabs> VUE 3：如何使用组合 API 获取有关 Tabs 组件中子项的一些信息？获取长度，迭代它们，并创建选项卡标题，...等？有任何想法吗？（使用组合API）这是我现在的 Vue 3 组件。我使用 Provide 来获取子 Tab 组件中的信息。 <template> <div class="tabs"> <div class="tabs-header"> <div v-for="(tab, index) in tabs" :key="index" @click="selectTab(index)" :class="{'tab-selected': index === selectedIndex}" class="tab" > {{ tab.props.title }} </div> </div> <slot></slot> </div> </template> <script lang="ts"> import {defineComponent, reactive, provide, onMounted, onBeforeMount, toRefs, VNode} from "vue"; interface TabProps { title: string; } export default defineComponent({ name: "Tabs", setup(_, {slots}) { const state = reactive({ selectedIndex: 0, tabs: [] as VNode<TabProps>[], count: 0 }); provide("TabsProvider", state); const selectTab = (i: number) => { state.selectedIndex = i; }; onBeforeMount(() => { if (slots.default) { state.tabs = slots.default().filter((child) => child.type.name === "Tab"); } }); onMounted(() => { selectTab(0); }); return {...toRefs(state), selectTab}; } }); </script> 选项卡组件： <script lang="ts"> export default defineComponent({ name: "Tab", setup() { const index = ref(0); const isActive = ref(false); const tabs = inject("TabsProvider"); watch( () => tabs.selectedIndex, () => { isActive.value = index.value === tabs.selectedIndex; } ); onBeforeMount(() => { index.value = tabs.count; tabs.count++; isActive.value = index.value === tabs.selectedIndex; }); return {index, isActive}; } }); </script> <template> <div class="tab" v-show="isActive"> <slot></slot> </div> </template> 哦伙计们，我解决了： this.$slots.default().filter(child => child.type.name === 'Tab') 对于想要完整代码的人：标签.vue <template> <div> <div class="tabs"> <ul> <li v-for="tab in tabs" :class="{ 'is-active': tab.isActive }"> <a :href="tab.href" @click="selectTab(tab)">{{ tab.name }}</a> </li> </ul> </div> <div class="tabs-details"> <slot></slot> </div> </div> </template> <script> export default { name: "Tabs", data() { return {tabs: [] }; }, created() { }, methods: { selectTab(selectedTab) { this.tabs.forEach(tab => { tab.isActive = (tab.name == selectedTab.name); }); } } } </script> <style scoped> </style> 标签.vue <template> <div v-show="isActive"><slot></slot></div> </template> <script> export default { name: "Tab", props: { name: { required: true }, selected: { default: false} }, data() { return { isActive: false }; }, computed: { href() { return '#' + this.name.toLowerCase().replace(/ /g, '-'); } }, mounted() { this.isActive = this.selected; }, created() { this.$parent.tabs.push(this); }, } </script> <style scoped> </style> 应用程序.js <template> <Tabs> <Tab :selected="true" :name="'a'"> aa </Tab> <Tab :name="'b'"> bb </Tab> <Tab :name="'c'"> cc </Tab> </Tabs> <template/> 我扫描子元素的解决方案（在对 vue 代码进行大量筛选之后）是这样的。 export function findChildren(parent, matcher) { const found = []; const root = parent.$.subTree; walk(root, child => { if (!matcher || matcher.test(child.$options.name)) { found.push(child); } }); return found; } function walk(vnode, cb) { if (!vnode) return; if (vnode.component) { const proxy = vnode.component.proxy; if (proxy) cb(vnode.component.proxy); walk(vnode.component.subTree, cb); } else if (vnode.shapeFlag & 16) { const vnodes = vnode.children; for (let i = 0; i < vnodes.length; i++) { walk(vnodes[i], cb); } } } 这将返回子组件。我对此的用途是我有一些通用的对话框处理代码，用于搜索子表单元素组件以咨询其有效性状态。 const found = findChildren(this, /^(OSelect|OInput|OInputitems)$/); const invalid = found.filter(input => !input.checkHtml5Validity()); 如果你复制粘贴与我相同的代码然后只需向“选项卡”组件添加一个创建的方法，该方法将自身添加到其父级的选项卡数组中 created() { this.$parent.tabs.push(this); }, 使用脚本设置语法，您可以使用useSlots：https://vuejs.org/api/sfc-script-setup.html#useslots-useattrs <script setup> import { useSlots, ref, computed } from 'vue'; const props = defineProps({ perPage: { type: Number, required: true, }, }); const slots = useSlots(); const amountToShow = ref(props.perPage); const totalChildrenCount = computed(() => slots.default()[0].children.length); const childrenToShow = computed(() => slots.default()[0].children.slice(0, amountToShow.value)); </script> <template> <component :is="child" v-for="(child, index) in childrenToShow" :key="`show-more-${child.key}-${index}`" ></component> </template> 我对 Ingrid Oberbüchler 的组件做了一个小改进，因为它不支持热重载/动态选项卡。在 Tab.vue 中： onBeforeMount(() => { // ... }) onBeforeUnmount(() => { tabs.count-- }) 在 Tabs.vue 中： const selectTab = // ... // ... watch( () => state.count, () => { if (slots.default) { state.tabs = slots.default().filter((child) => child.type.name === "Tab") } } ) 我也遇到了同样的问题，在做了很多研究并问自己为什么他们删除了$children之后，我发现他们创建了一个更好、更优雅的替代方案。这是关于动态组件的。 (<component: is =" currentTabComponent "> </component>). 我在这里找到的信息： https://v3.vuejs.org/guide/component-basics.html#dynamic-components 希望这对你有用，向大家问好！！我发现这个更新的 Vue3 教程使用 Vue 插槽构建可重用的选项卡组件对于与我相关的解释非常有帮助。它使用 ref、provide 和ject 来替换我遇到同样问题的this.tabs = this.$children;。我一直在遵循我最初发现的构建选项卡组件（Vue2）的教程的早期版本创建您自己的可重用 Vue 选项卡组件。根据 Vue 文档，假设您在 Tabs 组件下有一个默认插槽，您可以直接在模板中访问该插槽的子级，如下所示： // Tabs component <template> <div v-if="$slots && $slots.default && $slots.default()[0]" class="tabs-container"> <button v-for="(tab, index) in getTabs($slots.default()[0].children)" :key="index" :class="{ active: modelValue === index }" @click="$emit('update:model-value', index)" > <span> {{ tab.props.title }} </span> </button> </div> <slot></slot> </template> <script setup> defineProps({ modelValue: Number }) defineEmits(['update:model-value']) const getTabs = tabs => { if (Array.isArray(tabs)) { return tabs.filter(tab => tab.type.name === 'Tab') } else { return [] } </script> <style> ... </style> 并且 Tab 组件可能类似于： // Tab component <template> <div v-show="active"> <slot></slot> </div> </template> <script> export default { name: 'Tab' } </script> <script setup> defineProps({ active: Boolean, title: String }) </script> 实现应类似于以下内容（考虑一组对象，每个部分一个，带有 title 和 component）： ... <tabs v-model="active"> <tab v-for="(section, index) in sections" :key="index" :title="section.title" :active="index === active" > <component :is="section.component" ></component> </app-tab> </app-tabs> ... <script setup> import { ref } from 'vue' const active = ref(0) </script> 另一种方法是使用 useSlots，如 Vue 文档（上面的链接）中所述。在 3.x 中，$children 属性已被删除并且不再受支持。相反，如果您需要访问子组件实例，他们建议使用 $refs。作为数组 https://v3-migration.vuejs.org/writing-changes/children.html#_2-x-syntax 在 3.x 版本中，$children 已被删除且不再受支持。使用 ref 访问子实例。 <script setup> import { ref, onMounted } from 'vue' import ChildComponent from './ChildComponent .vue' const child = ref(null) onMounted(() => { console.log(child.value) // log an instance of <Child /> }) </script> <template> <ChildComponent ref="child" /> </template> 详细信息：https://vuejs.org/guide/essentials/template-refs.html#template-refs 基于@Urkle的回答： /** * walks a node down * @param vnode * @param cb */ export function walk(vnode, cb) { if (!vnode) return; if (vnode.component) { const proxy = vnode.component.proxy; if (proxy) cb(vnode.component.proxy); walk(vnode.component.subTree, cb); } else if (vnode.shapeFlag & 16) { const vnodes = vnode.children; for (let i = 0; i < vnodes.length; i++) { walk(vnodes[i], cb); } } } 除了已接受的答案之外：而不是 this.$root.$children.forEach(component => {}) 写 walk(this.$root, component => {}) 这就是我让它为我工作的方式。

获取不可编辑、灰色但内容可选的输入元素

我有和元素，其内容在某些步骤中不应可编辑。因此，最初我向这些元素添加了一个禁用属性。元素</desc> <question vote="0"> <p>我有 <pre><code><input type="text"></code></pre> 和 <pre><code><textarea></code></pre> 元素，其内容在某些步骤中不应可编辑。</p> <p>所以，最初我为这些元素添加了 <pre><code>disabled</code></pre> 属性。这些元素变得不可编辑并且呈灰色。这个行为很好。</p> <p>但是，它们的内容应该是可选择的，而 <pre><code>disabled</code></pre> 属性避免了这种情况。所以我切换到了 <pre><code>readonly</code></pre> 属性。元素仍然不可编辑，内容可以选择，但不再是灰色的。</p> <p>因此，我正在寻找一种解决方案来包含以下元素：不可编辑、可选择和灰显。</p> <ul> <li>我可以应用一些 CSS，但我更喜欢禁用输入的本机浏览器样式。</li> <li>这些元素不是<pre><code><form></code></pre>的一部分，因此无需担心表单提交。</li> </ul> </question> <answer tick="false" vote="0"> <p>要在不使用disabled属性的情况下实现具有不可编辑、可选择和灰显元素的所需行为，您可以使用CSS和readonly属性的组合。您可以设置只读元素的样式，使其看起来像已禁用，同时保留选择其内容的能力。以下是如何实现此目标的示例：</p> <pre><code>input[readonly], textarea[readonly] { color: #777; /* Set text color to a muted color */ background-color: #eee; /* Set background color to a light grey */ cursor: not-allowed; /* Show a not-allowed cursor to indicate non editable state */ } /* Adjust the style for textareas, if needed */ textarea[readonly] { resize: none; /* Disable textarea resizing */ } </code></pre> <pre><code> <input type="text" readonly> <textarea readonly></textarea> </code></pre> </answer> </body></html>

错误：在此 BlocBuilder<InternetBloc> Widget<InternetBloc, InternetState> 上方找不到正确的提供程序

我在尝试将 flutter_bloc 集成到 flutter 项目中时遇到错误。错误：在此 BlocBuilder 上方找不到正确的 Provider 我在尝试将 flutter_bloc 集成到 flutter 项目中时遇到错误。错误：在此 BlocBuilder Widget 上方找不到正确的提供者这是我正在使用的代码示例。 internet_state.dart abstract class InternetState{} class InitialInternetState extends InternetState{} class LostConnectionInternetState extends InternetState{} class GainConnectionInternetState extends InternetState{} internet_event.dart abstract class InternetEvent{} class LostConnectionEvent extends InternetEvent{} class GainConnectionEvent extends InternetEvent{} internet_bloc.dart class InternetBloc extends Bloc<InternetEvent, InternetState>{ final Connectivity _connectivity = Connectivity(); StreamSubscription? streamSubscription; InternetBloc() : super(InitialInternetState()){ on<GainConnectionEvent>((event, emit) => emit(GainConnectionInternetState())); on<LostConnectionEvent>((event, emit) => emit(LostConnectionInternetState())); _connectivity.onConnectivityChanged.listen((event) { if(event == ConnectivityResult.mobile || event == ConnectivityResult.wifi){ add(GainConnectionEvent()); } else { add(LostConnectionEvent()); } }); } @override Future<void> close() { streamSubscription?.cancel(); return super.close(); } } main.dart class MyApp extends StatelessWidget { const MyApp({super.key}); @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple), useMaterial3: true, ), home: const MyHomePage(title: 'Flutter Demo Home Page'), ); } } class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(title: Text(title),), body: SafeArea( child: Center(child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, )), ),); } } 我明白了。 ======== 小部件库捕获异常====================================== =================== 构建 MediaQuery(MediaQueryData(size: Size(392.7, 783.3), devicePixelRatio: 2.8, textScaler: noscaling, platformBrightness: Brightness.light, padding: EdgeInsets.zero, viewPadding: EdgeInsets.zero, viewInsets: EdgeInsets 时抛出以下 ProviderNotFoundException。零，systemGestureInsets：EdgeInsets（29.8，24.0，29.8，8.0），alwaysUse24HourFormat：假，accessibleNavigation：假，highContrast：假，onOffSwitchLabels：假，disableAnimations：假，invertColors：假，boldText：假，navigationMode：传统，gestureSettings：DeviceGestureSettings （touchSlop：8.0），显示功能：[]））：错误：无法在此 BlocBuilder Widget 之上找到正确的提供程序发生这种情况是因为您使用了不包含提供程序的 BuildContext 你的选择。有以下几种常见场景：您在main.dart中添加了一个新的提供程序并执行了热重载。要修复此问题，请执行热重启。您尝试阅读的提供商处于不同的路线。提供商具有“范围”。因此，如果您在路线中插入提供者，那么其他路线将无法访问该提供商。您使用了 BuildContext，它是您尝试读取的提供程序的祖先。确保 BlocBuilder 位于您的 MultiProvider/Provider 下。当您创建提供程序并尝试立即读取它时，通常会发生这种情况。例如，代替： Widget build(BuildContext context) { return Provider<Example>( create: (_) => Example(), // Will throw a ProviderNotFoundError, because `context` is associated // to the widget that is the parent of `Provider<Example>` child: Text(context.watch<Example>().toString()), ); } 考虑使用builder，如下所示： Widget build(BuildContext context) { return Provider<Example>( create: (_) => Example(), // we use `builder` to obtain a new `BuildContext` that has access to the provider builder: (context, child) { // No longer throws return Text(context.watch<Example>().toString()); } ); } 如果这些解决方案都不起作用，请考虑在 StackOverflow 上寻求帮助： https://stackoverflow.com/questions/tagged/flutter The relevant error-causing widget was: SafeArea SafeArea:file:///Users/../Projects/flutterTest/bloc_test/lib/main.dart:37:13 When the exception was thrown, this was the stack: #0 Provider._inheritedElementOf (package:provider/src/provider.dart:343:7) #1 Provider.of (package:provider/src/provider.dart:293:30) #2 ReadContext.read (package:provider/src/provider.dart:649:21) #3 _BlocBuilderBaseState.initState (package:flutter_bloc/src/bloc_builder.dart:130:36) #4 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:5602:55) #5 ComponentElement.mount (package:flutter/src/widgets/framework.dart:5447:5) ... Normal element mounting (4 frames) #9 Element.inflateWidget (package:flutter/src/widgets/framework.dart:4326:16) #10 Element.updateChild (package:flutter/src/widgets/framework.dart:3831:20) #11 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #12 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #13 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #14 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #15 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #16 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #17 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #18 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #19 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #20 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #21 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #22 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #23 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #24 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #25 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #26 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #27 StatelessElement.update (package:flutter/src/widgets/framework.dart:5547:5) #28 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #29 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #30 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #31 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #32 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #33 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #34 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #35 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #36 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #37 Element.updateChildren (package:flutter/src/widgets/framework.dart:3964:32) #38 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6896:17) #39 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #40 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #41 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #42 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #43 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #44 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #45 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #46 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #47 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #48 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #49 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #50 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #51 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #52 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #53 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #54 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #55 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #56 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #57 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #58 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #59 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #60 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #61 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #62 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #63 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #64 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #65 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #66 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #67 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #68 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #69 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:6743:14) #70 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #71 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #72 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #73 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #74 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #75 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #76 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #77 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #78 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #79 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #80 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #81 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #82 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #83 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #84 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #85 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #86 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #87 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #88 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #89 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #90 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #91 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #92 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #93 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #94 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #95 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #96 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #97 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #98 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #99 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #100 ProxyElement.update (package:flutter/src/widgets/framework.dart:5800:5) #101 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #102 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #103 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5634:11) #104 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #105 StatefulElement.update (package:flutter/src/widgets/framework.dart:5657:5) #106 Element.updateChild (package:flutter/src/widgets/framework.dart:3815:15) #107 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5496:16) #108 Element.rebuild (package:flutter/src/widgets/framework.dart:5187:7) #109 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2895:19) #110 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:984:21) #111 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:457:5) #112 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1325:15) #113 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1255:9) #114 SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:978:7) #118 _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12) (elided 3 frames from class _Timer and dart:async-patch) ==================================================================================================== 我不想使用像 MultiProvider 这样的全局提供程序。您应该在某处创建 InternetBloc 并提供它。 MultiProvider 本身并不是全局的，它只是多个。更多信息在这里：https://bloclibrary.dev/#/flutterbloccoreconcepts?id=blocprovider 所以，如果您不想使用全局提供程序，它将看起来像这样： class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(title), ), body: SafeArea( child: Center( child: BlocProvider<InternetBloc>( create: ( context) => InternetBloc(), child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, ), ), ), ), ); } } 要使用 BlocBuilder，您需要在 Widget 树中放置一个 BlocProvider。最佳实践是将其放置得尽可能深。在您的情况下，只需将 BlocProvider 放在 BlocBuilder 之上。此外 MultiProvider / MultiBlocProvider 不是全局 Provider。它只是一个提供多个 Provider/BlocProvider 的便捷小部件。 class MyHomePage extends StatelessWidget { const MyHomePage({super.key, required this.title}); final String title; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(title), ), body: SafeArea( child: Center( // Now everything below that can access the InternetBloc child: BlocProvider<InternetBloc>( create: (_) => InternetBloc(), child: BlocBuilder<InternetBloc, InternetState>( builder: (context, state) { return const Text("hello"); }, ), ), ), ), ); } }

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