bootstrap-vue 多级下拉菜单

Question

我正在使用 bootstrap-vue，并且我有一个多级下拉菜单（用于类别）。这是官方网站示例：

https://bootstrap-vue.org/docs/components/dropdown

<b-dropdown id="dropdown-1" text="Dropdown Button" class="m-md-2">
  <b-dropdown-item>First Action</b-dropdown-item>
  <b-dropdown-item>Second Action</b-dropdown-item>
</b-dropdown>

但我不知道如何创建多级菜单（我在彼此之间复制下拉菜单，但它不起作用）！它只有 1 级下拉示例！我怎样才能创建一个多层次的？

tnx

Answer 1

正如我在 cmets 中提到的，您可以包装 b-dropdown 事件并执行如下自定义操作：

window.onload = () => {
  new Vue({
    el: '#app',
    data() {
      return {
        name: 'BootstrapVue',
        isDropdown2Visible: false
      }
    },
    mounted: function () {
      this.$root.$on('bv::dropdown::show', bvEvent => {
        if(bvEvent.componentId === 'dropdown-2') {
          this.isDropdown2Visible = true;
        }
        })
      this.$root.$on('bv::dropdown::hide', bvEvent => {
        if(bvEvent.componentId === 'dropdown-2') {
          this.isDropdown2Visible = false;
        }
        if(this.isDropdown2Visible) {
          bvEvent.preventDefault()
        }
        })
    }
  })
}

body { padding: 1rem; }

<link type="text/css" rel="stylesheet" href="https://unpkg.com/bootstrap@4.5.3/dist/css/bootstrap.min.css" />
<link type="text/css" rel="stylesheet" href="https://unpkg.com/bootstrap-vue@2.21.2/dist/bootstrap-vue.css" />

<script src="https://unpkg.com/vue@2.6.12/dist/vue.min.js"></script>
<script src="https://unpkg.com/bootstrap-vue@2.21.2/dist/bootstrap-vue.min.js"></script>

<div id="app">
  <b-dropdown id="dropdown-1" text="Dropdown Button 1" class="m-md-2">
    <b-dropdown-item>First Action 1</b-dropdown-item>
    <b-dropdown-item>Second Action 1</b-dropdown-item>
    <b-dropdown id="dropdown-2" text="Dropdown Button 2" class="m-md-2">
        <b-dropdown-item>First Action 2</b-dropdown-item>
        <b-dropdown-item>Second Action 2</b-dropdown-item>
    </b-dropdown>
  </b-dropdown>
</div>

Answer 2

你可以试试这样的

此 sn-p 包含一级菜单的逻辑。您可以将代码编辑为 根据您的要求

JSBin Link

new Vue({
  el: "#app",
  data: {
    menu: [
        { title : 'one'},
      { title : 'two'},
      { title : 'three',showSubMenu : false,
        children : [
          { title : 'four'},
          { title : 'five'},
      ]},
    ]  
  },
  methods : {       
    toogleItem(index){
      if(this.menu[index].children){
          if(!this.menu[index].showSubMenu){
            this.menu[index].showSubMenu = true
          } else {
            this.menu[index].showSubMenu = false
          }
      }
      
    }
  }
})

.sub-menu{
  position: absolute;            
    min-width: 10rem;
    padding: .5rem 0;
    margin: .125rem 0 0;
    font-size: 1rem;
    color: #212529;
    text-align: left;
    list-style: none;
    background-color: #fff;
    background-clip: padding-box;
    border: 1px solid rgba(0,0,0,.15);
    border-radius: .25rem;
}

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
  <!-- Load required Bootstrap and BootstrapVue CSS -->
<link type="text/css" rel="stylesheet" href="//unpkg.com/bootstrap/dist/css/bootstrap.min.css" />
<link type="text/css" rel="stylesheet" href="//unpkg.com/bootstrap-vue@latest/dist/bootstrap-vue.min.css" />

<!-- Load polyfills to support older browsers -->
<script src="//polyfill.io/v3/polyfill.min.js?features=es2015%2CIntersectionObserver" crossorigin="anonymous"></script>

<!-- Load Vue followed by BootstrapVue -->
<script src="//unpkg.com/vue@latest/dist/vue.min.js"></script>
<script src="//unpkg.com/bootstrap-vue@latest/dist/bootstrap-vue.min.js"></script>

<!-- Load the following for BootstrapVueIcons support -->
<script src="//unpkg.com/bootstrap-vue@latest/dist/bootstrap-vue-icons.min.js"></script>
</head>
<body>

<div id="app">  
  <b-dropdown id="dropdown-1" text="Dropdown Button" class="m-md-2">
    <b-dropdown-item 
     v-for="(item,index) in menu"  
     :key="index"
     @mouseover.native="toogleItem(index)"
     @mouseout.native="toogleItem(index)">
      <span>{{item.title}} <b-icon-caret-down-fill :scale="0.6" v-if="item.children"></b-icon-caret-down-fill></span>
        <div v-if="item.children" class="sub-menu" v-show="item.showSubMenu">
            <b-dropdown-item v-for="(item,index) in item.children" :key="index">{{item.title}}
            </b-dropdown-item>   
        </div>
    </b-dropdown-item>   
  </b-dropdown>
</div>
</body>
</html>