vue下拉菜单组件（含搜索）的实现代码

<template>
  <div class="vue-dropdown default-theme">
   <div class="cur-name" @click="isshow =! isshow">{{itemlist.cur.name}}</div>
   <div class="list-and-search" :class="isshow?'on':''">
   <div class="search-module clearfix" v-show="isneedsearch">
       <input class="search-text" 
       @keyup='search($event)' :placeholder="placeholder" />
     </div>
     <ul class="list-module">
       <li v-for ="(item,index) in datalist" @click="selecttoggle(item)" 
       :key="index">
         <span class="list-item-text">{{item.name}}</span>
       </li>
     </ul>
     <div class="tip-nodata" v-show="isneedsearch && datalist.length == 0">{{nodatatext}}</div>
   </div>
  </div>
</template>

<script>
  export default {
    data(){
      return {
        datalist:[],
        isshow:false
      }
    },
    props:{
      'itemlist':object,//父组件传来的数据
      'placeholder':{
       type:string,
       default: '搜索' //input placeholder的默认值
      },
      'isneedsearch':{ //是否需要搜索框
       type:boolean,
       default: false
      },
      'nodatatext':{ //是否需要显示搜索
       type:string,
       default: '未找到结果' //没有搜索到时的文本提示
      }  
    },
    created(){
     this.datalist = this.itemlist.data;
      //点击组件以外的地方，收起
      document.addeventlistener('click', (e) => {
       if (!this.$el.contains(e.target)){
         this.isshow = false; 
       }
      }, false)
    },
    methods:{
      selecttoggle(data){
       this.itemlist.cur.name = data.name;
       this.isshow = false;
        this.$emit('item-click',data);
      },
      search(e){
        let searchvalue = e.currenttarget.value;
        this.datalist = this.itemlist.data.filter((item,index,arr)=>{
          return item.name.indexof(searchvalue) != -1;
        });
      }
    }
  }
</script>

<style lang="less" scoped>
 .list-and-search{
 background: #fff;
 border: 1px solid #ccc;
 display: none;
   &.on{
     display: block;
    }
 }
 .cur-name{
 height: 32px;
 line-height: 32px;
 text-indent: 10px;
 position: relative;
 color: #777;
 &:after{
  position: absolute;
   right: 9px;
   top: 13px;
   content: " ";
   width: 0;
   height: 0;
   border-right: 6px solid transparent;
   border-top: 6px solid #7b7b7b;
   border-left: 6px solid transparent;
   border-bottom: 6px solid transparent;
 }
 &.show{
  &:after{
  right: 9px;
    top: 6px;
    border-right: 6px solid transparent;
    border-bottom: 6px solid #7b7b7b;
    border-left: 6px solid transparent;
    border-top: 6px solid transparent;
  }
 }
 }
  .vue-dropdown.default-theme {
    width: 200px;
    z-index:10;
    border-radius:3px; 
    border: 1px solid #ccc;
    cursor: pointer;
    -webkit-user-select:none; 
 user-select:none;
    &._self-show {
      display: block!important;
    }
    .search-module {
      position: relative;
      border-bottom: 1px solid #ccc;
      .search-text {
        width: 100%;
        height: 30px;
        text-indent: 10px;
        // border-radius: 0.5em;
        box-shadow: none;
        outline: none;
        border: none;
        // &:focus {
        //   border-color: #2198f2;
        // }
      }
      .search-icon {
        position: absolute;
        top: 24%;
        right: 0.5em;
        color: #aaa;
      }
    }
    input::-webkit-input-placeholder{
     font-size: 14px;
    }
    .list-module {
      max-height: 200px;
      overflow-y: auto;
      li {
        &._self-hide {
          display: none;
        }
        margin-top: 0.4em;
        padding: 0.4em;
        &:hover {
          cursor:pointer;
          color: #fff;
          background: #00a0e9;
        }
      }
    }
  }
  .tip-nodata {
    font-size: 14px;
    padding: 10px 0;
    text-indent: 10px;
  }
</style>

<dropdown :item-click="dropdownclick" :isneedsearch="true" :itemlist="itemlist"></dropdown>
import dropdown from '@/components/dropdown.vue'
export default {
 data() {
  return {
    itemlist: {
    cur: {
     val: "",
     name: "所有产品"
    },
    data: [{
     val: "",
     name: "所有产品"
    }, {
     val: 1,
     name: "梦幻西游"
    }, {
     val: 2,
     name: "梦幻无双"
    }, {
     val: 3,
     name: "大话西游"
    }]
   },
  }
 },
 components: {
  dropdown,
 },
 methods :{
  dropdownclick(e) {
   console.log(e.name, e.val)
  }
 }
}